WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 2.1 Classification of Kingdom Animalia offer valuable context and analysis.

WBBSE Class 9 Science Chapter 2.1 Question Answer – Biomolecules and their Behaviour

Very Short Questions and Answers : (1 mark for each question)

Question 1.
What are we made up of?
Answer:
We are made up of millions of inorganic and organic molecules.

Question 2.
How do we denote the large molecules of the body of an organism?
Answer:
We denote the large molecules of the body of an organism as macromolecules.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 3.
How do we denote the elements, which we need in a very little quantity?
Answer:
The elements that are required in very little quantity in the body of an organism are denoted as micromolecules.

Question 4.
Which simple compound does a living cell need the most, for survival?
Answer:
Water is a simple compound, which a living cell needs the most, for its survival.

Question 5.
What are biomolecules?
Answer:
Biomolecules are the organic molecules produced or involved in various biochemical reactions within the cells or inside the body.

Question 6.
Which inorganic acid plays a very important role in our digestion process?
Answer:
Hydrochloric acid is the inorganic acid, which plays an important role in our digestion process.

Question 7.
What does carbonic acid do in our body?
Answer:
Carbonic acid is involved in the transportation of CO2, out of the body, via respiratory exchange of gases.

Question 8.
Which gas is involved in energy generation in a living body?
Answer:
Oxygen is involved in the energy generation in a living body.

Question 9.
Which anabolic process needs CO2?
Answer:
Photosynthesis is the anabolic process, which needs CO2.

Question 10.
Which is the most abundant salt in our body?
Answer:
Sodium chloride (NaCl) is the most abundant salt in our body.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 11.
Which two elements are essential for our skeletal system?
Answer:
Calcium and phosphorus are the two elements essential for our skeletal system.

Question 12.
What is the similarity among monosaccharides, amino acids and fatty acids?
Answer:
Monosaccharides, amino acids and fatty acids are all organic micromolecules.

Question 13.
What is the basic difference between nucleotides and a nucleic acid?
Answer:
Nucleotides are organic micromolecules and nucleic acid is an organic macromolecule.

Question 14.
Which type of sugars cannot be hydrolysed into smaller carbohydrates?
Answer:
Monnsaccharfths cannot be hydrolysed into smaller carbohydrates.

Question 15.
Which type of sugar is called a disaccharide?
Answer:
The sugar having two monosaccharide units is called a disaccharide.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 16.
How do you denote tite sugars composed of 3 to 9 monosaccharide units?
Answer:
The sugars with 3 to 9 monosaccharide units are denoted as oligosaccharides.

Question 17.
Which type of sugars is generally insoluble in water and tasteless in nature?
Answer:
Polysaccharides are generally insoluble in water and tasteless in nature.

Question 18.
What is calorltic value?
Answer:
blat heat energy liberated by the complete oxidation of Unit mass of a matter is known as its calorific value.

Question 19.
How much heat energy is liberated from one gram of glucose on its complete oxidation?
Answer:
On complete oxidation of one gram of glucose molecule, 4A kcal heat energy is liberated.

Question 20.
What is the full form of MUFA?
Answer:
The full form of MUFA is Mono Unsaturilted Fatty Acid.

Question 21.
Which type of biomolecule is commonly consumed by organisms for energy generation?
Answer:
Living organisms commonly consume carbohydrates for energy generation.

Question 22.
Which type of biomolecule is commonly consumed by organisms as body building materials?
Answer:
Living organisms commonly consume proteins as body building materials.

Question 23.
Which type of biomolecule do living organisms commonly store within the body?
Answer:
Living organisms commonly store fat within the body.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 24.
Which type of material in food helps in faeces formation and facilitate defecation?
Answer:
A polysaccharide, called cellulose, helps in face formation and facilitates defecation.

Question 25.
Which type of food should a growing baby be fad with?
Answer:
A Growing baby should be fed with protein-rich food for maximum muscular growth.

Question 26.
How are the two strands of a DNA molecule zipped together?
Answer:
The two strands of a DNA molecule are zipped together by weak hydrogen bonds between the bases.

Question 27.
Name the bond by which nucleosides of a nucleic acid strand remain attached one after another.
Answer:
The nucleosides of a nucleic acid strand remain attached one after another by phosphate bonds.

Question 28.
Which nucleic acid is mainly involved in carrying hereditary features from parents to oftsprings?
Answer:
Mainly DNA is involved in carrying hereditary features from parents to offsprings.

Question 29.
Which type of organisms synthesise most of the vitamins?
Answer:
Green plants synthesise most of the vitamins.

Question 30.
Which vitamin is synthesised within our skin on exposure to sun?
Answer:
Vitamin D is synthesised within our skin on exposure to sun.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 31.
Which type of vitamin should a person take in for problems with vision after sunset?
Answer:
A person having problems with vision after sunset should take vitamin A.

Question 32.
Give an example of an aldose sugar.
Answer:
Glucose is an example of aldose sugar.

Question 33.
Which two elements are essential for neural transport?
Answer:
Sodium and potassium are necessary for neural transport.

Question 34.
Which two simplest molecular units form a lipid molecule?
Answer:
Fatty acid and glycerol are the two simplest molecular units, which form a lipid molecule.

Question 35.
Name a reducing sugar.
Answer:
Glucose is a reducing sugar.

Question 36.
Name a non-reducing sugar.
Answer:
Sucrose is a non-reducing sugar.

Question 37.
Name two fat soluble vitamins present in egg.
Answer:
Vitamin A and vitamin D are two fat soluble vitamins present in egg.

Question 38.
Which mineral is essential for haemoglobin formation?
Answer:
Iron is essential for haemoglobin formation.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 39.
Which element is involved in the formation of thyroxin hormone?
Answer:
Iodine is involved in the formation of thyroxine hormone.

Question 40.
Name a mineral essential for muscle contraction and blood coagulation.
Answer:
Calcium is essential for muscle contraction and blood coagulation.

Question 41.
What is the ratio of hydrogen and oxygen in carbohydrates?
Answer:
In carbohydrates, hydrogen and oxygen are present in the ratio of 2: 1.

Question 42.
Give an example of a ketohexose.
Answer:
Fructose is an example of a ketohexose.

Question 43.
Name a basic protein.
Answer:
Histone is a basic protein.

Question 44.
What is the chemical name of vitamin P?
Answer:
Chemical name of vitamin P is citrine.

Question 45.
Name an iron-containing enzyme.
Answer:
Catalase is an iron-containing enzyme.

Question 46.
Name two triose sugars.
Answer:
Two triose sugars are monotriose and dihydroxyacetone.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 47.
Name the sweetest carbohydrate.
Answer:
The sweetest carbohydrate is fructose or fruit-sugar.

Question 48.
In animal body, fat is stored in which tissue?
Answer:
In animal body, fat is stored in adipose tissue.

Question 49.
Which disease is caused in children due to deficiency of iodine?
Answer:
Cretinism is caused in children, due to deficiency of iodine.

Question 50.
Name two vitamins present in lemon.
Answer:
Vitamin C (ascorbic acid) and vitamin P (citrine) are two vitamins present in lemon.

Question 51.
What is the chemical name of vitamin D?
Answer:
Chemical name of vitamin D is calciferol.

Question 52.
Deficiency of which vitamin results in teeth and gum deformity?
Answer:
Deficiency of vitamin C results in deformity of teeth and gums.

Question 53.
What is the minimum number of monosaccharides required to form a polysaccharide?
Answer:
At least 10 monosaccharide molecules are necessary to constitute a polysaccharide.

Question 54.
What is the main function of vitamin A in human?
Answer:
Vitamin A helps in the production of rhodopsin pigment in rod cells of human eye.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 55.
What is meant by a polypeptide?
Answer:
Large polymers of numerous amino acid molecules, linked together by peptide bonds, are known as polypeptides.

Short Questions and Answers : (2 marks for each question)

Question 1.
Schematically represent the molecules of life.
Answer:
Molecules of life are mentioned in the following chart-
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 1

Question 2.
Why are different molecules so important for our existence?
Answer:
Life has originated from different non-living molecules through complex chemical reactions. These molecules build our body as well as help to maintain all our life processes. That is why, these are important for our existence.

Question 3.
Mention the roles of two biologically important gases, which organisms absorb directly from atmosphere.
Answer:
Oxygen and carbon dioxide are the two biologically important gases, which organisms absorb directly from atmosphere. All aerobic organisms utilise oxygen to oxidise glucose and liberate energy, necessary to run their life processes. All autotrophs use carbon dioxide as the raw material for photosynthesis to prepare their food.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 4.
Mention the roles of an acid and a base in human body.
Answer:
Hydrochloric acid, secreted in stomach, converts pepsinogen into active pepsin to start digestion of protein, HCl also helps to hydrolyse sucrose. Sodium bicarbonate, present in bile, is basic in nature, which neutralises the acidic contents of stomach as soon as it reaches the duodenum.

Question 5.
Classify biomolecules based on their molecular weight and give two examples for each.
Answer:
On the basis of molecular weight, organic molecules or biomolecules can be differentiated into two basic types. These are – bio-micromolecules and bio-macromolecules. Examples of bio-micromolecules are mono-saccharides, amino acids etc. Examples of bio-macromolecules are proteins, nucleic acids etc.

Question 6.
What is meant by carbohydrates? Give two examples.
Answer:
Carbohydrates are the organic compounds made up of carbon, hydrogen and oxygen, in which hydrogen and oxygen maintain a ratio of 2:1. Examples — Glucose and cellulose.

Question 7.
Why are carbohydrates called saccharides? Give any two examples of two different types of saccharides.
Answer:
Naturally occurring carbohydrates or the end products of their hydrolysis are sweet to taste. In Greek, ‘saccharides’ means sugars, therefore, carbohydrates are commonly called saccharides. Saccharides are of different types – mono, oligo and polysaccharides. Two example of monosaccharides are glucose and fructose and two examples of oligosaccharides are sucrose and raffinose.

Question 8.
Mention plant and animal carbohydrates.
Answer:
Carbohydrates are mostly found in different plant products – rice, wheat, maize, potato, beet, arum are the sources of starch. Various fruits like mango, banana, oranges etc. provide fructose. Juice of date-palm plant, sugarcane are rich in sucrose and glucose. All green vegetables and some fruits, like wood apple, water melon etc. are good sources of cellulose. Milk is an animal product that contains milk sugar (lactose).
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 2

Question 9.
what is meant by sugars? Give example of two biologically important sugars.
Answer:
Carbohydrates with low molecular weight, high water solubility and sweet taste are called sugars.
Example -Two biologically important sugars are glucose and fructose.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 10.
What is glycosidic bond?
Answer:
The bond that develops between two or more monosaccharide units to form disaccharide, oligosaccharide or polysaccharide molecules is known as glycosidic bond.

Question 11.
What is meant by monosaccharides? Mention the basic molecular formula of monosaccharides.
Answer:

  • Monosaccharides: Monosaccharides are the simplest form of carbohydrates, which have low molecular weight, high water solubility, sweet taste and cannot be hydrolysed further into smaller carbohydrates. Fructose is one type of monosaccharide.
  • Molecular formula: The basic molecular formula of carbohydrate is (CH2O)n.

Question 12
What is meant by disaccharides? Give two examples of biologically important disaccharides.
Answer:
Disaccharides are the sweet tasting, watersoluble carbohydrates, composed of two monosaccharide molecules. Examples-Sucrose and lactose are the two biologically important disaccharides.

Question 13.
What are oligosaccharides? Mention the basic molecular formula of oligosaccharides.
Answer:

  • Oligosaccharides: Oligosaccharides are the complex type of carbohydrates, which are composed of 3 to 9 monosaccharide units. Example-Raffinose.
  • Molecular formula: The basic molecular formula of oligosaccharides is Cn(H2O)n-1

Question 14.
What are polysaccharides? Mention the basic molecular formula of polysaccharides.
Answer:
Polysaccharides: Polysaccharides are water insoluble and tasteless type of complex carbohydrates, composed of ten to numerous monosaccharide units. Example-Cellulose.
Molecular formula: The basic molecular formula is (C6H10O5)n

Question 15
Why carbohydrates are called ‘protein sparing food’?
Answer:
By consuming adequate carbohydrates, an organism can survive without taking dietary proteins. Within the body, these carbohydrates are transformed into amino acids by some metabolic processes. These amino acids consequently form different proteins. Therefore, carbohydrates are called ‘protein sparing food.’
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 3

Question 16
What is meant by amino acid? Give example.
Answer:
An amino acid is the structural and functional unit of a protein which is composed of carbon, hydrogen, oxygen and nitrogen, typically possessing an amino (-NH6) group and a carboxyl (-COOH) group.
Example-Glycine, Alanine, Histidine etc.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 17.
What is an ester?
Answer:
The organic compound, that is formed by the reaction of an alcohol and an organic acid, is called ester. Example-Glycerides phosphoester.

Question 18.
What are proteins? Give example.
Answer:
Proteins are biologically important macromolecules, composed of either a number of amino acids or a combination of amino acids and few non-amino acid components, acting as the building materials of all living bodies. Example – Albumin, Globulin, Haemoglobin etc.

Question 19.
Mention two characteristic features of proteins.
Answer:
Two characteristic features of proteins are as follows-

  • Proteins are polymers of amino acids which are basically composed of carbon, hydrogen, oxygen and nitrogen.
  • Proteins are mostly soluble in water and they coagulate on heating.

Question 20.
What is meant by simple proteins? Give example.
Answer:
The proteins, which do not contain anything other than amino acids, joined by peptide bonds, are known as simple proteins. Example – Albumin, Globulin, Glutenin etc.

Question 21.
What is meant by conjugated proteins? Give example.
Answer:
The proteins which are composed of amino acids and some non-amino acid components, are called conjugated proteins. Example – Haemoglobin, Haemocyanin, Cytochrome etc.

Question 22
What is meant by derived proteins?
Answer:
Certain proteins are produced during the hydrolytic breakdown of larger protein molecules. These are called derived proteins. Example – Peptone, Metaprotein, Proteose etc.

Question 23.
What is meant by basic amino acids? Give example.
Answer:
The amino acids which have two or more basic amino groups (-NH2), are called basic amino acids.
Example – Lysine, Arginine, Histidine etc.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 24.
What is meant by acidic amino acids? Give example.
Answer:
The amino acids which have two or more acidic carboxyl groups (-COOH), are called acidic amino acids. Example – Glutamic acid, Aspartic acid etc.

Question 25.
What is meant by essential amino acids? Give example.
Answer:
The acids, which are indispensable for normal growth and development, but are not synthesised within the body and can only be taken in as food, are known as essential amino acids.
Example: Tryptophan, Phenylalanine, Threonine, Valine, Methionine, Leucine, Isoleucine.

Question 26
Mention the sources of proteins.
Answer:
Proteins are available in both animal and plant products. Animal sources of proteins are fish, meat, egg and milk. Among plant sources, pulses, soyabean, gram etc. are rich in proteins. Rice, wheat, certain fruits and vegetables also contain a little bit of protein.
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 4

Question 27.
Mention the importance of protein in human body.
Answer:
Protein is the building block of our body. For this reason, the body needs adequate supply of proteins through food. Deficiency of protein may lead to retardation of physical as well as mental growth. Development of brain, eye, bones and muscles will be affected the most. Several physiological activities are also hampered due to protein deficiency.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 28.
Mention two diseases caused due to protein malnutrition.
Answer:
Marasmus and Kwashiorkor are two commonly known diseases which are caused due to protein malnutrition.
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 5
Question 29.
What is meant by fatty acids? Give example.
Answer:
Fatty acids are the smaller biomolecules, composed of three elements like carbon, hydrogen and oxygen, having a hydrocarbon chain ending with a carboxyl (-COOH}) group and taking part in the formation of lipids. ExampleLanoline, Linolenic acid.

Question 30.
Why egg is called the reference protein?
Answer:
Egg contains almost all proteins in perfect proportions as per requirement of the body. Nutritionists, therefore measure the nutritional value of other proteins with reference to the proteins present in egg, so egg is known as the reference protein.

Question 31.
What is meant by saturated fatty acid?
Answer:
The fatty acids in which carbon atoms are joined to each other by monovalent bonds, are known as saturated fatty acids. ExamplePalmitic acid, Stearic acid etc.

Question 32.
What is meant by unsaturated fatty acid?
Answer:
The fatty acids in which carbon atoms are joined to each other by bivalent or trivalent bonds, are known as unsaturated fatty acids. Example-Linolenic acid, Linoleic acid etc.

Question 33.
What is meant by lipids? Mention the dietary sources of lipids.
Answer:

  • Lipids: The esters of fatty acids and alcohols which are insoluble in water but soluble in organic solvents like acetone, benzene, chloroform, ether etc., are known as lipids.
  • Sources of lipids: Butter, ghee, oils, coconut, different types of oil seeds, red meat are the common dietary sources of lipids.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 6

Question 34.
What is meant by essential fatty acids?
Answer:
Certain physiologically important fatty acids are never synthesised within the body. We get it from dietary fats. These are called essential fatty acids. Example-Linolenic acid, Linoleic acid are two essential fatty acids.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 35.
Classify lipids. Give an example of each type.
Answer:
The following chart shows different types of lipids with one example of each.
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 7

Question 36
What is meant by simple lipids? Give example.
Answer:
The lipids which are composed of esters of different fatty acids and glycerol only, are called simple lipids. Example-Lanoline, Wax etc.

Question 37.
What is meant by conjugated lipids? Give example.
Answer
Certain types of lipids are composed of some other substances beside fatty acids and glycerol, these are called conjugated lipids. Example-Phospholipid, Glycolipid etc.

Question 38.
What is meant by derived lipids? Give example.
Answer:
Derivatives of lipids or biologically active lipid-like compounds, are called derived lipids.
Example-Prostaglandins, Steroids etc.

Question 39.
Mention the physical characteristic features of lipids.
Answer:
The physical characteristic features of lipids are as follows-

  • Lipids are colourless, tasteless and odourless substances,
  • Lipids are insoluble in water but soluble in organic solvents like ether, benzene, chloroform etc.
  • Due to low specific gravity all lipids float in water.

Question 40.
Mention two importances of lipid in a living organism.
Answer:
Two importances of lipid in a living organism are as follows-

  • Lipids are the reserve food materials of plants and animals.
  • Lipid is one of the main structural components of cell membrane.

Question 41.
What is meant by fat? Give example.
Answer:
The triglycerides which remain in solid or semi-solid state at room temperature, are called fat. One example of plant fat is margarine and that of animal fat is butter.

Question 42
What is meant by wax? Give example.
Answer:
Wax is a solidified ester of a fatty acid and an alicyclic or aliphatic monohydric alcohol other than glycerol. Example-Lanoline, Bee-wax etc.

Question 43.
What is meant by organic oil? Give example.
Answer:
The glycerides which are hydrophobic, lipophilic, slippery substances, with low melting points and remain in liquid state at room temperature, are called organic oils. ExampleCoconut oil, mustard oils etc.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 8

Question 44.
What is nucleoside?
Answer:
Nucleoside is an elementary part of a nucleic acid composed of any one of the purines or pyrimidines bases and a pentose sugar of either ribose or deoxyribose type.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 45
What is meant by nucleic acid? Give example.
Answer:
The largest biological macromolecule, composed of several nucleotides, occuring in all living cells for storing and transmitting hereditary characters and genetic information, is known as nucleic acid. Example-Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

Question 46
Classify different types of nitrogenous bases found in nucleic acids.
Answer:
The following chart shows different types of nitrogenous bases found in nucleic acids.
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 9

Question 47.
Where does DNA occur?
Answer:
DNA occurs inside the protein capsule of DNA-virus. In eukaryotic cells, it is present in chromosomes within the nucleus. It is also present in the matrix of their mitochondria and plastids. In prokaryotic cells, it is present as a circular DNA, but it lies naked in the cell cytoplasm in a specialised region called nucleoid.

Question 48.
Write two functions of DNA.
Answer:
Two functions of DNA are as follows-

  • DNA transmits hereditary characters from parents to offspring.
  • DNA controls all gene-regulated biological activities.

Question 49.
What is RNA?
Answer:
RNA is the ribose sugar containing single stranded bio-macromolecule, which acts as the genetic material in Ribovirus and helps DNA to perform its hereditary and genetic activities in eukaryotic cells as well as helps in protein synthesis.

Question 50
What are vitamins?
Answer:
Vitamins are special components of food which are present in very little quantities, but they perform an elementary role in various physiological activities and in development of immunity against different diseases. Examplesvit. A, vit. B, vit. C, vit. D, vit. K etc.

Question 51.
What is meant by anti-vitamins? Give an example.
Answer:
Certain organic compounds hinder the functions of some vitamins or denature some vitamins completely. These compounds are known as anti-vitamins. Example-Galactoflavin is an anti-vitamin, which hinders the action of vitamin B12 or riboflavin.

Question 52.
What is a pseudo-vitamin? Give an example.
Answer:
A pseudo-vitamin is a substance that has a chemical structure similar to that of a vitamin but lacks the usual physiological effects of a vitamin. Example-Methylcobalamin is the pseudovitamin of vitamin B12

Question 53.
What is a provitamin? Give an example.
Answer:
The organic compound from which vitamin is synthesised in the body of a living organism, is called a provitamin. Example-vitamin A is synthesised in the liver from the provitamin β Carotene.

Question 54.
Mention the functions of vitamin A in human body.
Answer:
The functions of vitamin A in human body are as follows-

  • Vitamin A helps to maintain health of eye, tear gland and retina.
  • It helps in maintaining healthy skin and muscle.

Question 55
Why vitamin A is called anti-xerophthalmic vitamin?
Answer:
Xerophthalmia is defined as the condition characterised by excessive and abnormal dryness of the eye-ball, accompanied by conjunctivities. This occurs basically due to the deficiency of vit.A. Since, vit.A prevents Xerophthalmia, therefore it is called anti-xerophthalmic vitamin.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 56.
Mention the functions of vitamin D in human body. Mention its sources.
Answer:
Functions:

  • Vitamin D helps in the uptake of phosphorus and calcium from the intestine.
  • It helps in the formation of teeth and bones.

Sources: The sources of vit.D are milk, cabbage, vegetable oil, cod liver oil etc.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 10

Question 57.
Why vitamin D is called anti-ricketic vitamin?
Answer:
Ricket is a vit.D deficiency disease. Since vit.D helps in the prevention of the disease, therefore it is called as anti-ricketic vitamin.

Question 58.
Which vitamin is called anti-sterility vitamin? Mention the main functions of this vitamin.
Answer:
Anti-sterility vitamin: Vitamin E is called antisterility vitamin
Functions of vitamin E:

  • Vitamin E helps in the development of embryo, reproductive organs and muscles.
  • It helps to inhibit unwanted oxidation in the body by substances called free radicals.

Question 59
Which vitamin is called anti-haemorrhagic vitamin? Mention the functions of this vitamin.
Answer:
Anti-haemorrhagic vitamin: Vitamin K is called the anti-haemorrhagic vitamin.
Functions of vitamin K:

  • Vitamin K helps in prothrombin formation and blood coagulation.
  • It helps in the normal energy production in mitochondria.

Question 60
Which vitamin is called anti-scorbutic vitamin? Mention the functions of this vitamin.
Answer:
Anti-scorbutic vitamin: Vitamin C is called antiscrobutic vitamin, since it helps in preventing the disease scurvy.
Function of vitamin C:

  • It protects the body against some infections like common cough and cold.
  • It helps in the development of teeth and bones.
  • It catalyses the metabolism of carbohydrates.

Question 61
Mention the functions of vitamin B3.
Answer:
The functions of vitamin B3 are as follows:

  • It catalyses the transformation of carbohydrates to lipids.
  • It helps to stimulate the central nervous system.
  • It helps in cellular respiration and metabolism.

Question 62
Which two vitamins help in cellular respiration? What is the similarity between iron and vitamin B12 ?
Answer:
Both vitamin B1 and B2 help in cellular respiration.
Both iron and vitamin B12 help in the formation of red blood cells.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 63.
Mention one function of chlorine. Write a function of manganese.
Answer:
Function of chlorine: Chlorine helps to maintain the acid-base balance in the body.
Function of manganese: Manganese regulates the normal level of carbohydrate in the blood.

Question 64.
How do minerals control membrane permeability?
Answer:
Potassium (K) increases membrane permeability of living cells whereas calcium (Ca) restricts it. Thus, mineral elements play important role in controlling membrane permeability in the body.

Question  65
Write the names of some plant and animal sources of food which are rich in magnesium.
Answer:

  • Plant sources of magnesium: The plant sources of magnesium are green vegetables, grains, groundnut, bean, soyabean, peas etc.
  • Animal sources of magnesium: The animal sources of magnesium are fish, chicken, egg, milk etc.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 11

Question 66.
Write the names of some plant and animal sources of food which are rich in iron.
Answer:
Plant sources of iron: The plant sources of iron are pulses, whole-wheat flour, spinach, lettuce, banana etc.
Aninal sources of iron: The animal sources of iron are fish, egg, mutton, liver etc.WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 12

Question 67.
Which elements and vitamins help in the formation of our skeletal structure?
Answer:
Calcium (Ca) and phosphorus (P) are the main building components of bones and teeth. Similarly, vitamin D and vitamin C are the vitamins which also help in the formation of teeth and bones. Thus, these elements and vitamins take part in the formation of the skeletal structure of the human body.

Question 68
Mention two animal sources and a plant source of calcium.
Answer:
Two animal sources of calcium are fish and egg and a plant source of calcium is peas.
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 13

Question 69
What are the functions of sodium in human body?
The functions of sodium in human body are as follows-

  • It helps to maintain cardiac systole, blood pressure, blood volume and acid-base balance.
  • It helps in the flow of nerve impulse.
  • It also helps to maintain the density of urine.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 70.
Mention a plant source and an animal source of sodium.
Answer:
A plant source of sodium is vegetables and an animal source of sodium is butter.
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 14

Question 71.
Distinguish between oligosaccharides and polysaccharides.
Answer:

Features Oligosaccharides Polysachharides
1. Number of monosaccharide units Made up of 3-9 monosaccharide units Made up of 10 or more than 10 monosaccharide units
2. Solubility Soluble in water Insoluble in water
3. Taste Sweet Tasteless

Question 72.
Distinguish between amino acids and fatty acids.
Answer:

Features Amino acids Fatty acids
1. Occurence Structural unit of proteins Structural unit of lipids
2. Chemical structure Each molecule has one amino (-NH2) and one carboxylic (-COOH) group Each molecule has one methyl (-CH2) and one carboxylic (-COOH) group and one intermediate ethyl (-CH2) group
3. Function Join with polypeptides to synthesise enzymes, hormones and to form cell components Prepare different membranes of cell and cell organelies. Participate in lipid synthesis.

Question 73.
Distinguish between simple carbohydrates and complex carbohydrates.
Answer:

Features Simple carbohydrates Complex carbohydrates
1. Number of monosaccharide units Made up of one or two monosaccharide units Made up of more than two monosaccharide units
2. Nutritional value Quickest source of energy, lack fibre Rich in fibre, vitamins and minerals
3. Biological significance Get oxidised in respiration to generate energy Build cellular membranes and act as stored food

Question 74.
Distinguish between nucleotides and nucleosides.
Answer:

Features Nucleotides Nucleosides
1. Structural components Pentose sugar, nitrogenous base and phosphate Pentose sugar and nitrogenous base
2. Nature Acidic Slightly basic
3. Role Structural unit of nucleic acids Structural portion of a nucleotide


Long Questions and Answers : (5 marks for each question)

Question 1.
Briefly describe the role of water in a living body. Mention the importance of different gases and salt in living organisms.
Answer:
Role of water in living body
The role of water in living body are as follows—

  • Body of a living organism consists of 70-90% water. Water acts as the medium of all cellular reactions within protoplasm.
  • In plants, water helps in photosynthesis, ascent of sap, germination of seeds and transpiration.
  • In animals, water is the major component of body fluid. It helps in digestion, excretion and maintains salt and water balance.
  • In squids and echinoderms, water helps in locomotion also.

Importance of different gases in living organisms
Oxygen and carbon dioxide are the two most biologically important gases. Their importance are as follows—

  • Oxygen is essential for respiration in all aerobic organisms to oxidise food and to liberate energy.
  • Carbon dioxide is the raw material, utilized by all the autotrophs for photosynthesis.

Importance of salt in living organisms
The importance of salt in living organisms are as follows—

  • Salt maintains osmoregulation in body.
  • Salt controls the production of thyroid hormone.
  • Salt helps to form structure of bones.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 2.
Briefly mention the main characteristic features of carbohydrates and its importances in living body.
Answer:
Main characteristic features of carbohydrate
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 15
The main characteristic features of carbohydrates are mentioned below.

  • Carbohydrates are colourless, odourless and mosdy water-soluble (polysaccharides are insoluble in water) organic compounds.
  • Smaller carbohydrates (monosaccharides and disaccharides) are sweet tasting, hence, they are known as sugars.
  • Carbohydrates behave as reducing molecules due to presence of aldehyde and ketone in them.
  • In larger carbohydrate molecules, monosaccharide units may arrange in either linear or circular manner.

Importance of carbohydrates in living body
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 16
The importance of carbohydrates in living body are as follows —

  • Monosaccharides (glucose and fructose) act as fuel to fulfill body’s energy need. Calorific value of carbohydrate is 4.1 kcal/g.
  • Structural components of cell wall, cell-coat and blood group antigens are carbohydrates.
  • Glucose and other sugars are transformed into fats and amino acids by some physiological processes.
  • Most animals are incapable of digesting cellulose. So it is accumulated in the intestine as roughage, which in turn, helps in bowel formation.

Question 3.
Classify monosaccharides based on the number of carbon atoms. Mention the characteristic features of monosaccharides.
Classification of monosaccharides
Based on the number of carbon atoms, monosaccharides can be classified into the following types.

  • Triose: These monosaccharides are composed of three carbon atoms. Example-Glyceraldehyde.
  • Tetrose: These monosaccharide molecules have four carbon atoms. Example-Erythrose.
  • Pentose: Five carbon atoms are present in a pentose monosaccharide. Example-Ribose.
  • Hexose: This is the most commonly occuring monosaccharide, which is composed of six carbon atoms. Example-Glucose, fructose etc.
  • Heptose: Few monosaccharides are of this type, which have seven carbon atoms.
    Example-Sedoheptulose.

Characteristic features of monosaccharides
The characteristic features of monosaccharides are as follows-

  • These are crystalline solids at room temperature and quite soluble in water. Monosaccharides are colourless, sweet substances.
  • These are reducing sugars, reduces mild oxidising agents because they have free ketone or aldehyde group.
  • These produce glycoside bond when react with alcohol and form enediol compound when react with base.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 4.
How do proteins take part in different life processes?
Answer:
Role of proteins in different life processes
Proteins take part in different life processes. These are mentioned below.

  • Proteins are the building materials of a living cell.
  • Proteins are directly involved in the development of embryo, growth, healing of wounds, repair of damaged tissues etc.
  • Proteins are the main structural components of animal cell membrane and cell organelles, different body tissues, different enzymes, hormones and antibodies and several other substances.
  • Nucleoproteins constitute chromosomes, which carry genes.
  • Protein is also a major source of energy. Calorific value of protein is 4.1kcalg.
  • Broken non-nitrogenous amino acids produce carbohydrates and fats by the process of deamination and trans-amination.
  • Proteins act as buffer solution to maintain the pH of body.
  • In mammals, proteins play important role in production of milk during lactation.

Question 5.
Schematically represent different types of proteins. Give a brief account of different proteins based on nutritional value. Mention the sources.
Answer:
Schematic representation of different types of protein

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 17

Different proteins based on nutritional value
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 18
Nutritional value of proteins depends upon the number of essential amino acids present in it.

  • First class protein: The proteins which contain all essential amino acids in perfect proportion Sources of protein necessary for building our body are treated as first class proteins. Sources-Different animal proteins like milk, meat, fish, egg etc.
  • Second class proteins: The proteins which may contain essential amino acids but not in perfect proportion, which is necessary for building the body, or lack a few essential amino acids, are known as second class proteins. Sources-Pulses, gram, rice, wheat etc.
  • Third class proteins: These proteins do not contain essential amino acids, hence, play no role as body building material, these are merely catabolised to generate heat. Source-Gelatin.

Question 6.
Mention the role of essential fatty acids in our body.
Answer:
Role of essential fatty acids
The role of essential fatty acids in our body are mentioned below.

  • Essential fatty acids are responsible for keeping the skin glowing and wrinkle-free.
  • These help in maintaining membrane permeability of skin cells.
  • These help in maintaining steady supply of milk in mammary glands of lactating mothers.
  • Essential fatty acids help to maintain water balance in the body.
  • These fatty acids help in growth and extend reproductive life.
  • These help in transporting cholesterol in blood.
  • Function of kidney is further supported due to the presence of some essential fatty acids.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 7.
Mention two biological importance of fatty acids. Write down the roles of lipids in life processes.
Answer:
Importance of fatty acids
Two biological importance of fatty acids are as follows-

  • Fatty acids are the units of fat, which is one of the most important structural components of the body.
  • Products of many fatty acids act as hormones.

Roles of lipids in life processes
The roles of lipids in life processes are as follows-

  • Lipids act as the reserve food materials of plants and animals.
  • Fat can generate maximum heat energy. Its calorific value is 9.3kcalg. Animals like frogs, snake etc. store fat in the adipose cells under their skin, which protect them against extreme cold.
  • Fat deposits in the body of desert animals (such as camels) are oxidised to produce metabolic water, to counter extreme dryness.

Question 8
Describe the structure of a nucleotide. Mention the main roles of nucleotides in life processes.
Answer:
Structure of nucleotide
Nucleotides are the units of nucleic acids. Several nucleotide monomers join in a linear sequence to constitute a nucleic acid molecule. A nucleotide is composed of three components-

  • A pentose (5C) sugar,
  • A nitrogenous base and
  • A phosphate group.

A nucleotide monomer without phosphate is called nucleoside. Practically, A phosphate group holds two successive nucleosides together. Nucleotides have two basic types of nitrogenous bases-

  • Purines (include adenine and guanine)
  • Pyrimidines (include thymine, cytosine and uracil).

Pentose sugar is also of two types-

  • ribose and
  • deoxyribose.

Roles of nucleotides in life processes
The main roles of nucleotides in life processes are as follows-

  • Nucleotides play an important role in cell signalling and metabolism.
  • The specific arrangement of nucleotides on a nucleic acid stores genetic information for performing all the biochemical activities in all living organisms.

Question 9.
Schematically represent the different components of a DNA molecule. Briefly describe the structure of a DNA molecule.
Answer:
Components of a DNA molecule
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 19

Structure of a DNA molecule
A DNA molecule is a double-stranded, coiled, helical structure, running in opposite directions and made up of a several nucleotide units. Many nucleotide monomers join in a linear sequence in two parallel strands to constitute a DNA molecule. The structural unit of DNA is composed of a sequence of deoxyribonucleotides. Such a nucleotide is composed of three components-

  • A five carbon containing deoxyribose sugar,
  • Any one of the four nitrogenous bases (viz. adenine, guanine, thymine and cytosine) and
  • A phosphate group. Practically, two successive nucleosides are held together by a phosphate group to constitute a DNA strand.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 20

The two strands of a DNA molecule are zipped together by weak hydrogen bonds. Here, adenine joins with thymine by two hydrogen bonds (A=T) and guanine joins with cytosine by three hydrogen bonds (G≡C).

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 10.
Mention the similarities and dissimilarities of DNA and RNA.
Answer:
Similarities between DNA and RNA
The similarities between DNA and RNA are as follows-

  • Both DNA and RNA are nucleic acids.
  • Both are made up of pentose sugar, nitrogenous base and phosphate.
  • Both are treated as bio-macromolecules.
  • DNA and RNA carry same types of purines, i.e. adenine and guanine.
  • Cytosine is present in both these molecules.

Dissimilarities between DNA and RNA

Features DNA RNA
1. Occurrence Nucleus, mitochondria and plastids Cytopasm and ribosomes
2. Physical structure Double stranded helical molecule Single stranded molecules with some loops
3. Type of sugar Deoxyribose sugar Ribose sugar
4. Nitrogenous base Adenine, guanine, thymine and cytosine Adenine, guanine, uracil and cytosine
5. Genetic activity Acts as the genetic material in all living cells Acts as the genetic material in some viruses
6. Function Give all genetic commands to control every reaction and activity in a living cell or a living body Helps in synthesis of polypeptide chains according to the command of DNA

Question 11.
What is atherosclerosis? Mention the effects of fluorine overdose in human body.
Answer:
Atherosclerosis
When cholesterol percentage becomes excessive in blood, cholesterol is deposited and forms plaque on the inner wall of arteries. Thus, the arterial wall becomes thick. This condition is called as atherosclerosis. Atherosclerosis enhances the chances of heart failure.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 21
Effects of fluorine overdose in human body
Presence of excess fluorine in drinking water has harmful effects on the teeth. The enamel of the teeth becomes weak and turns brownish in colour. It also results in the formation of cavity leading to a condition called dental fluorosis.

Apart from this, fluorine forms a cementing layer on spine and bones of legs, resulting in the loss of their natural flexibility. In addition to this, high fluoride ingestion can also cause a range of gastro-intestinal symptoms like nausea, pain and vomiting. Moreover, excess fluoride level in body results in polyuria (frequent urination), polydipsia (excessive thirst) and constipation followed by diarrhoea.
WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour 22

Question 12
Mention the role of different types of vitamin B in human body.
Answer:
Role of vitamin B in human body
Role of different types of vitamin B in human body are as follows-

1. Vitamin B1 (Thiamin):

  • It helps in the oxidation of sugars in brain and muscular tissues.
  • It catalyses the synthesis of proteins, fats and carbohydrates.
  • It helps in general growth of the body.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

2. Vitamin B2 (Riboflavin):

  • It helps in cellular respiration.
  • It helps in maintaining healthy skin.
  • It catalyses the transformation of carbohydrates into fat.

3. Vitamin B3 (Nicotinic acid or Niacin):

  • It catalyses the transformation of carbohydrates into lipids.
  • It helps to stimulate the central nervous system.
  • It helps in cellular respiration and metabolism.

4. Vitamin B5 (Pantothenic acid):

  • It helps in the production of neurotransmitters in the body.
  • It helps to relieve the human body from a number of detrimental problems, like asthma.
  • It helps to prevent several neural problems like insomnia, depression etc.

5. Vitamin B6 (Pyridoxine):

  • It catalyses the transformation of starch and proteins into fat.
  • It helps in the synthesis of haemoglobin.
  • It helps in protein metabolism.

6 Vitamin B9/M (Folic acid):

  • It helps to produce healthy RBCs.
  • It helps in DNA formation.
  • It helps to maintain pregnancy and reduces the chance of premature delivery.

7. Vitamin B12 (Cyanocobalamine):

  • It helps in hemopoiesis or formation of RBC.
  • It catalyses the synthesis of nucleic acid.
  • It helps to maintain normal growth and activity of nervous system.

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 13.
Differentiate between water-soluble vitamins and fat-soluble vitamins.
Answer:
Differences between water-soluble vitamins and fat-soluble vitamins

Features Water-soluble vitamins Fat-soluble vitamins
1. Absorption medium Vitamins get dissolved in water and are absorbed through blood Vitamins get dissolved in fat and are absorbed through blood
2. Storage These vitamins get stored according to the need of the body These vitamins get stored in the body in excess quantity and cause hypervitaminosis
3. Necessity These vitamins should be taken regularly with food These vitamins remain stored in the body and utilised whenever need arises
4. Wastage During cooking, heat results in partial destruction, or, wastage of these vitamins During cooking, wastage or destruction of these vitamins is much less than that of water-soluble vitamins
5. Example Vitamin B-complex, vitamin C, vitamin P Vitamin A, vitamin D, vitamin E, vitamin K

Question 14.
Mention the various functions of amino acids. What is biological value of protein?
Answer:
Various functions of amino acids
The various functions of amino acids are as follows-

  • Formation of protoplasm: Amino acids help in the formation of protoplasm in living cells. They also help in the production of proteins like elastin, keratin etc.
  • Regulation of chemical reactions: Amino acids help in the synthesis of enzymes and also regulate different essential chemical reactions in the body.
  • Formation of haemoglobin: They also help in the proper formation of haemoglobin.
  • Antibody production: Amino acids help to produce antibodies in the body, which fight against many disease causing germs.
  • Glucose formation: They heip in the formation of glucose by the process of gluconeogenesis.

Biological value of protein
Biological value of protein is a measure of the proportion of absorbed protein from a food, which becomes incorporated into the proteins of the organism. In adults, total protein consumed is not utilised in body building, instead, it is used in healing and rest is removed through excretion. The part of protein which is assimilated after absorption in the body, is the biological value of protein.

It is measured with the following formula-
\(\text { Biological value of protein }=\frac{\text { Nitrogen incorporated into the body on the test day }}{\text { Nitrogen absorbed in proteins on the test day }} \times 100\)

WBBSE Class 9 Life Science Solutions Chapter 2.1 Biomolecules and their Behaviour

Question 15.
What do you understand by the terms macroelements and microelements? Mention general role of different minerais on physiological process of human body.
Answer:
Macroelements
The elements, which are required in large quantities for proper growth and development of human body, are known as macroelements. Example-Sodium (Na), potassium (K), chlorine (Cl), calcium (Ca), phosphorus (P) etc.

Microelements
The elements, which are required in minute quantities for proper growth and development of human body, are known as microelements. Example-Iron (Fe), boron (B), iodine (I), molybdenum (Mo), zinc (Zn), manganese (Mn), copper (Cu) etc.

General role of different minerals in human body
Different minerals play different roles on physiological processes, which are as follows-

  • As cofactors of enzymes: Different minerals like iron, copper, manganese, zinc etc. act as cofactors of the enzymes.
  • Maintenance of acid-base balance: Certain elements like sodium, potassium, chlorine etc. maintain acid-base balance within the body.
  • Maintenance of water balance: Sodium helps in maintaining water balance within the body.
  • Conduction of nerve impulse: Sodium and potassium play very important role in the conduction of nerve impulse.
  • Control membrane permeability: Elements like calcium and potassium control membrane permeability of our body.
  • Role in blood coagulation: Calcium acts as an essential blood-coagulating factor.
  • Formation of skeletal structure: Calcium and phosphorus are the main building components of bones and teeth.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 5.2 Natural Resources and its Sustainable Use offer valuable context and analysis.

WBBSE Class 9 Science Chapter 5.2 Question Answer – Natural Resources and its Sustainable Use

Very Short Questions and Answers : (1 mark for each question)

Question 1.
Name two natural resources.
Answer:
Two natural resources are forest and water.

Question 2.
What are the types of natural resources?
Answer:
Natural resources are of two types-

  1. Renewable natural resources
  2. Nonrenewable resources.

Question 3.
Name two renewable natural resources.
Answer:
Two renewable natural resources are water and wind.

Question 4.
Name two non-renewable natural resources.
Answer:
Two non-renewable natural resources are coal and petroleum.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 5.
In West Bengal, what percentage of land is under forest cover?
Answer:
16.5. % of West Bengal is covered by forest.

Question 6.
What percent of the total area of a country should be under forest cover?
Answer:
33 % of the total area of a country should be under forest cover.

Question 7
Name one economically important forest product.
Answer:
Wood is an economically important forest product.

Question 8.
Name some products, which we get from the forest.
Answer:
We get honey, timber, latex, resin etc. from forest.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 9.
What is the best way to conserve biodiversity?
Answer:
Afforestation is the best way to conserve biodiversity.

Question 10.
What is the medicinal utility of forest?
Answer:
Forest comprises several varieties of medicinal herbs, from which medicines are obtained.

Question 11.
What is the main cause of deforestation?
Answer:
Human population explosion is the main cause of deforestation.

Question 12.
Write down one natural cause of deforestation.
Answer:
Forest fire is a natural cause of deforestation.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 13.
Write down one man-made cause of deforestation.
Answer:
Urbanisation is a man-made cause of deforestation.

Question 14.
Which is the ‘natural buffer’ of an environment?
Answer:
Forest is the ‘natural buffer’ of an environment.

Question 15.
How much water on the earth do we get as freshwater?
Answer:
Only 2 % of the total water on the earth is utilised as freshwater.

Question 16.
In which two states of India, rain water harvesting is necessary.
Answer:
In Rajasthan and Gujrat, rain water harvesting is necessary.

Question 17.
By which natural process, earth gets freshwater?
Answer:
Earth gets freshwater in the form of rain.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 18.
Which branch of economic botany includes the cultivation of medicinally important herbs?
Answer:
Cultivation of medicinally important herbs is included under horticulture.

Question 19.
In Gangetic plains, which is the main source of dietary protein?
Answer:
Fish is the main source of dietary protein in the Gangetic plains.

Question 20.
Which decade was famous for green revolution?
Answer:
The decade of nineteen sixties was famous for green revolution.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 21.
Name of the food products of animal husbandry.
Answer:
The food products of animal husbandry are meat, milk and egg.

Question 22.
Name two edible mushrooms.
Answer:
Name of two edible mushrooms are Agaricus bisporus and Boletus edulis.

Question 23.
Mention one cause of global food crisis.
Answer:
Population explosion is an important cause of global food crisis.

Question 24.
Give some examples of fossil fuel.
Answer:
Some examples of fossil fuel are coal, petroleum, natural gas, mineral oil etc.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 25.
Mention one process of energy conservation in daily life.
Answer:
Using LED bulbs instead of ordinary bulbs reduces energy consumption atleast by \(\frac{2}{3}\) times.

Short Questions and Answers : (2 marks for each question)

Question 1.
What is meant by natural resources?
Answer:
Natural resources are those components, which occur in nature, are invaluable for humans and on which our survival depends.

Question 2.
What is meant by sustainable development?
Answer:
Sustainable development is the developmental process that meets the demand of the present, without destroying the scope of the future generation to meet their needs. In this process, industrial, agricultural and other developmental processes are carried out without causing any harm to the environment.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 3.
Why is sustainable development necessary?
Answer:
The natural resources that are present in our environment are continuously being utilized to maintain human lifestyle. With the advancement of human civilization and increase in population, these resources are being misused and wasted, rather than utilized. As a result, scientists and environmentalists have been trying to adopt measures to conserve these resources and save the environment, and subsequently carrying out all activities necessary for human development. For this reason, sustainable development is necessary.

Question 4.
What do you mean by forest?
Answer:
A forest is defined as a large area of land, that is covered with trees as well as other woody and non-woody vegetation. Forests are the predominant terrestrial ecosystem of earth and are distributed across the globe.

Question 5.
Why is forest considered as a resource?
Answer:
Forest plays important roles in improving the socio-economic condition of a country. They are-

  1. Forest serves as a source of raw materials for various industries.
  2. Forest serves as an important source of timber, which is used for making houses, furniture, boats etc.
  3. Forest serves as an important source for honey, latex, resin and other medicinal plants.
  4. Forest plays an important role in the conservation of biodiversity, regulation of climate and prevention of soil erosion. For these reasons forest is considered as an important natural resource.

Question 6.
What is meant by forest conservation?
Answer:
Forest conservation is the practice of maintaining forested areas for the benefit and sustainability of future generations. By this process over-utilization and improper use of forest resource is prevented and the biodiversity is conserved as well.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 7.
What is water cycle?
Answer:
Surface water from seas, lakes etc. evaporates to form water vapour and rises upwards. Transpiration by plants also contributes to this. This water vapour mixes with dust particles and combine with each other to form clouds. The clouds precipitate on the earth as rain, which mixes with rivers and streams and ultimately reverts back to sea. This continuous cyclic flow of water is known as water cycle.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 1

Question 8.
Write down two important effects of water cycle?
Answer:
Two important effects of water cycle are[1] It maintains water balance between landmass and water bodies. [2] It maintains the supply of drinking water and surface water.

Question 9.
What is ground water?
Answer:
The water present beneath the surface of the earth in the tiny spaces between soil particles to large fractures of rocks, is known as groundwater.

Question 10.
What is drinking water?
Answer:
The water that is safe enough for drinking and food preparation and does not cause any harm to human being, is known as drinking water. Drinking water is also known as potable water.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 11.
What do you mean by over-utilization of water?
Answer:
The water, collected from the surface and underground sources, are often misused or used indiscriminately. This is known as over-utilization of water.

Question 12.
Give examples of over-utilization of water.
Answer:
Over utilization of water occurs in many ways, such as-

  1. While brushing teeth, bathing and washing, leaving the tap running.
  2. In urban areas, fresh water is suctioned from underground much more than its normal demands, thereby lowering the underground reserve of fresh water.
  3. Agricultural fields are irrigated with underground water.
  4. Large amount of water is exploited in various industries.

Question 13.
Mention two causes of lowering of ground water level.
Answer:
Two causes of lowering of groundwater level are-

  1. The groundwater is suctioned in large quantity by means of motor pumps in order to meet human demands.
  2. In rural areas, huge quantity of groundwater is being used for irrigation.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 14.
Why is rain water considered pure as compared to the water of other water hodies?
Answer:
Only the water particles present on the surface of water bodies evaporate and accumulate to form clouds, which comes down as rain. The mineral salts or the harmful pollutants present in the water bodies do not evaporate to form clouds. As a result, these harmful particles do not come down with rain. So, rain water is considered pure as compared to the water of other water bodies.

Question 15.
What is meant by agriculture?
Answer:
Scientific practice of farming, including cultivation of soil for growing economically important crops and rearing of animals for food, wool, silk and other products, is called agriculture.

Question 16.
What is meant by horticulture?
Answer:
Horticulture is a branch of agriculture that includes the cultivation of fruits, vegetables, seeds medical plants, mushrooms, ornamental plants.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 2

Question 17.
What is meant by pisciculture?
Answer:
Pisciculture is a branch of agriculture that deals with the scientific practice of breeding, rearing and marketing of fish, prawn and other economically important aquatic animals.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 18.
What is poultry farming?
Answer:
Poultry farming is a branch of agriculture that deals with the scientific practice of breeding and rearing of birds like chicken, duck, quail, turkey etc. for meat and egg.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 3

Question 19.
What is meant by animal husbandry?
Answer:
Animal husbandry is the branch of agriculture that deals with the scientific practice of breeding and rearing of farm animals (cattle, sheep, poultry birds).

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 4

Question 20.
What is meant by energy crisis?
Answer:
With the development of industry and upliftment of lifestyle, the utilization of energy has increased to a great extent. But the generation of energy has not been increased to meet up that demand. This situation has developed a worldwide problem, that is popularly known as energy crisis.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 21.
Mention two common examples of wastage of electrical energy.
Answer:
Examples of wastage of electrical energy are as follows-

  1. Leaving the rooms, office, classrooms etc. vacant with fans and lights switched on.
  2. Keeping the street lights switched on duing the daytime.

Question 22.
What do you understand by energy resources?
Answer:
Energy resources are the main sources of energy from which energy can be extracted and utilized for mankind.

Question 23
What is a renewable natural resource?
Answer:
The renewable natural resources are those, which may drop quantitatively after being harvested but are replenished naturally after a certain period of time. Examples-Trees of forest, Population of fish etc.

Question 24.
What is a non-renewable natural resource?
Answer:
The non-renewable natural resources are those, which drop quantitatively after utilization and are never replenished by means. ExamplesCoal, Petroleum etc.

Question 25.
How different natural resources are intimately connected with our existence on earth?
Answer:
Forests, water, food and energy are the basic resources offered by nature. Forest acts as the habitat of life. It provides shelter to thousands of living organisms. Water is the main substance of life. Without water, no organism can survive. Food is the fuel of life, which provides energy, that perpetuates life. Thus, natural resources are intimately connected with our survival on earth.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 26.
What is White revolution?
Answer:
To achieve sustainability in milk production, advanced cattle breeding programme has been undertaken. This programme is called operation flood. Now this drive has shown its success. This is known as white revolution.

Question 27.
What is Blue revolution?
Answer:
To achieve the target of feeding the growing population of India, modern techniques of fish culture have been developed. This programme is popularly known as blue revolution, which has successfully reached its goal.

Question 28.
What is Green revolution?
Answer:
In the middle of sixties, in order to achieve sustainability in crop production, intensive agricuitural management has been practiced by applying hybrid crops, proper application of

Question 29.
fertilisers, agricultural equipments, proper irrigations etc. This is known as green revolution.
What is meant by food?
Answer:
The edible matters, which are taken in by the living organisms for nutrition, growth, generation of heat for physiological processes and to develop immunity against diseases, are collectively called food.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 5

Question 30.
What is SCP?
Answer:
Single cell protein (SCP) refers to the sources of mixed protein that has been extracted from pure or mixed culture of various microorganisms (such as algae, fungi or bacteria) and are used as protein-rich foods for human beings and animals. Example-Spirulina.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 6

Long Questions and Answers : (5 marks for each question)

Question 1.
Discuss the environmental and economic importance of a forest.
Answer:
Importance of a forest :
Importance of a forest is described below.
1. Watershed protection: Afforestation along the slope of watershed prevents runoff and reduces the deposition of slit in riverbed. Some plants with mycorrhizal root absorb heavy and toxic metals from soil and reduce the chance of water toxicity.

2. Atmospheric regulation: Scarcity of plants and excessive industrialization in urban areas reduces O2 and increases CO2 content in the atmosphere. Forest regulate O2-CO2 balance. By respiration organisms release CO2 and absorb O2 from the atmosphere. By the process of photosynthesis, green plants of a forest release O2 and absorb CO2. In this way, balance of O2 and CO2 in the atmosphere is maintained.

3. Erosion control: Erosion means washing or blowing away of top layer of soil. Forests prevent soil erosion by several methods. They are-

  • The branches of roots firmly bind the soil particles with the ground.
  • The dense leaves of forest prevent raindrops from hitting the soil particles directly and loosening it from the upper layer of soil.
  • The litter formed by the leaves on the forest floor, partly decompose to form sticky humus. This sticky humus increases the adhering capacity of the soil particles and prevents soil erosion.

4. Local use: Humans exploit forest in different ways. People living in nearby villages collect firewood from forest. Forest provide honey, timber, resin, honey, cotton, fur, wool, meat (from herbivores) etc. that are collected and marketed.

5. Productive use: From productive point of view, forest has immense importance. Timber is the main economically important product of forest, used to prepare sleepers, posts, log houses, plywood, laminates, galleries, furniture etc. Ecotourism is another productive aspect of the forest, from which the government earns huge amount of revenue. Honey, rubber and several medicinally important materials are collected from the forest.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 7

Question 2
Briefly discuss the causes of deforestation.
Answer:
Causes of deforestation :
The different causes of deforestation are discussed below-
1. Subsistence agriculture: It is an unscientific method of farming, where farmers concentrate on growing enough food for themselves and their family. They cut trees and burn smaller vegetation to prepare land for cultivation and cattle grazing.

2 Indiscriminate felling of trees: Growing population has increased demand of wood products, starting from match-sticks to furniture. Accordingly, price of wood has also been increased. Due to this high price of wood, traders encourage indiscriminate felling of trees.

3. Urbanisation: For development of the state infrastructure, roads and railway tracks are laid through forestland. Moreover, miners acquired the forestland for oil, coal and ore mining. This level of human intervention has affected the lifestyle of both animals and plants and leads to habitat fragmentation.

4. Forest fire: In drier seasons, the local farmers and forest communities burn dry grasses to expand grazing area. High concentration of oxygen in forest atmosphere drives this small fire into a firestorm. It goes out of control and destroys hundreds of trees and many smaller and bigger wild animals.

5. Desertification: Rivers and streams flowing through forestlands often carry industrial pollutants. These toxic materials cause soil pollution, which leads to polluting forest ecosystem.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 3.
Describe the consequences of deforestation.
Answer:
Consequences of deforestation :
Consequences of deforestation are as follows-
1. Global warming: Due to deforestation and rapid pace of industrialisation, concentration of greenhouse gases like CO2 increases in the atmosphere. This results in global warming.

2. Climatic change: Transpiration by trees increases humidity in atmosphere, which in turn enhances the chance of rainfall. In many parts of the world, rate of rainfall has dropped significantly due to deforestation.

3 Change of soil character and erosion: The litter, deposited in forest floor, decomposes to form humus, that keeps the soil healthy and moist in normal situation. Due to deforestation, soil gets exposed to sun and dries out. Moreover, soil particles become loose without binding of roots. Due to this, rain and wind washes off and blow away soil particles, reduce chance of humification resulting in soil erosion.

4. Flood and drought: Incidence of flood and drought has increased in every part of the world due to deforestation.

5. Wildlife extinction: Forests provide habitat for millions of species of flora and fauna. Deforestation makes them homeless. As a result, certain number of species as well as part of wildlife gets extinct.

6 Environmental pollution: Deforestation results in decrease in atmospheric oxygen level. At the same time carbon dioxide increases, which is a cause of air pollution. Mycorrhiza developing in the root system of some trees can remove heavy and toxic metals from the soil. In case of deforestation soil becomes polluted.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 8

Question 4.
Why should we conserve forests? Mention few methods of forest conservation.
Answer:
Reasons of forest conservation
Conservation is protection, augmentation and scientific management of resources so as to maintain them in their optimum level providing benefit to the present as well as future generations. Forests must be conserved because of their immense economic, protective and regulative properties. Forest conservation is important-

  • to maintain ecosystem of forest
  • to maintain O2 – CO2 balance in the environment
  • to maintain the supply of forest products like timber, food etc.
  • to maintain natural beauty and livelihood of the local people.

Methods of forest conservation

  1. Afforestation: It is growing of forests on unprotected barren lands.
  2. Reforestation: It is developing forest cover in the area which has been damaged or cleared during exploitation.
  3. Separation of commercial forestry: Useful plants required by industry should be planted separately preferably on waste land.
  4. Grazing: Grazing should be regulated according to the availability of pasturage.
  5. Social Forestry: It is growing of useful multipurpose trees and shrubs on common village lands, roadsides, railsides, etc. by cooperative efforts of people of the area. The plants provide fodder, small timber and fire wood to villagers.
  6. Agroforestry: Multipurpose trees and shrubs are planted on the sides of crop fields to provide fodder, fuel and timber.

Both social forestry and agroforestry reduce pressure on the forests. Trees are also planted at all vacant place and along roads in urban areas (urban forestry) for reducing air and noise pollution.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 5.
Mention the uses of water. Briefly describe the causes of water scarcity. 2 + 3
Answer:
Uses of water :
Water is an essential component of life. Water is one of the most vital natural resources on Earth for life to sustain. The availability and the quantity of water have always played a significant part in determining not only where population can grow but also their quality of life. It is used in several ways.

1. Drinking: Water is the most essential and a universal drink necessary for life.
2 Agriculture and industrial purpose: A large quantity of water is used for irrigation of crop fields. Different industries, such as metal, paper, chemical, wood, petrochemical etc. and boilers of power plants require large quantity of water. Water is used as raw material, solvent, coolant and washing medium.

Causes of water scarcity :
The main causes of global water scarcity are-

  1. Drop in rainfall: Rainfall has dropped radically in different parts of the world, resulting in moderate to severe water scarcity.
  2. Global warming: Excessive heat dries out surface water. But this loss is not totally replenished by rain.
  3. Over-utilisation of water: Over-utilization of ground water is a result of poor water management, that leads to water scarcity and increased chance of arsenic contamination.
  4. Pollution: Disposal of sewage water in streams and lakes is a wasteful technique. By this process, sources of freshwater are polluted and wasted.

Question 6.
How is rain water utilised to counter scarcity of fresh water. Mention the advantage and disadvantage of rain water harvesting? 3 + 2
Answer:
Utilisation of rain water :
Rain water is the largest source of fresh water. By scientific harvesting of rain water, the fresh water scarcity can be controlled to a great extent. Rain water harvesting is a simple and effective method of water management by which rain water is collected, stored and used to meet the demand for fresh water.

The easiest and popular method is rooftop rain water harvesting. In this process, rain water : of roof are connected to a ground level or underground reservoir. The rain water is stored ; reservoir and is used according to necessity. This water can be used directly for any non-F purposes like watering plants, washing and cleaning, bathing and toilets. For cooking and dr this water must be disinfected and filtered. For using rain water at community level, resecreasing and disinfected centrally and then pumped to the overhead water supply tank or the main well of the village.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 9

Advantages and disadvantages of rain water harvesting –
Advantages and disadvantages of rain water harvesting are as follows –
1. Advantages:

  • Rain water is generally free from germs and contaminants.
  • It is soft water with slightly acidic pH} and does not contain any salt.
  • Rain water contains no corrosive substances, so it does not harm water pipes and reservoirs.

2. Disadvantages: Rain water harvesting is not practiced in areas with excessive suspended particulate matters in air. Toxic gaseous materials pollute the atmosphere at regions near chemical industries and fertilizer factories. These gaseous pollutants mix with rain water and make it harmful.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 7.
Briefly describe different sources of food for human consumption.
Answer:
Different sources of food for human consumption –
Different sources of food for human consumption are mentioned below-
1. Crop production: The maximum quantity of food we consume are plant products. These include cereals (paddy, wheat, maize, millets etc.), pulses (moong, masur, gram, pea etc.) and oil seeds (mustard seed, sunflower seed, groundnut seed, rape seed etc.)

2. Horticulture: Horticulture includes the cultivation of fruits, vegetables, nuts, seeds, herbs etc. We get fruits and vegetables from horticultural farms. The fruits and vegetables which we use in cooking, are also horticultural products.

3. Cattle farming: This industry is involved in breeding and rearing of animals like cows, goats, pigs etc. It provides us with animal products like meat and milk.

4. Poultry: This industry is involved in breeding and rearing domestic birds like chickens, ducks etc. This industry provides us with poultry producers like meat and eggs.

5. Fishery: Fisheries are meant for scientific breeding and rearing of fishes. Fisheries supplies fishes to our platter.

Question 8.
Briefly describe the situation of food scarcity on global basis. Mention the impacts of food scarcity on earth. 2+3
Answer:
Global food scarcity :

During the last century, industrialization and urbanization have reached the peak. This situation has pushed agriculture already at the back row. Now the rate of agricultural production cannot neet the global demand of food crops. The environmental changes and increasing population have ggravated this problem. All these factors have developed scarcity of food all over the world.

The uation has become more adverse in poorer and developing countries. Out of 70 billion of total rld population, about 10 billion have been suffering from malnutrition and partial starvation. A millions are dying out of starvation or diseases caused by malnutrition. People of Africa, Latin serica and Asia are the main victims of food scarcity.

Impact of food scarcity :

Food scarcity is not only taking lives due to starvation and malnutrition, besides these, it also has some other impacts on human life and environment. To increase crop production, a land is cultivated two or three times in a year. In developing countries, chemical fertilizers are applied indiscriminately to increase yield. By this practice, the natural fertility of soil is lost, also the soil pH changes.

Forest lands are encroached upon by farming. This practice results in deforestation which is followed by soil erosion and flood. Random use of pesticides in the crop fields cause soil and water pollution that may result into many incurable diseases. Irrigation of crop fields by suction of underground water is reducing the underground water reserve and causing arsenic pollution.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 10

Question 9.
Refer to a specific incident related to world food probiem. Give examples of different alternative food sources. 2+3
Answer:
Special incident related to world food problem :
Between July 2011 and mid 2012, a severe drought affected the entire East Africa region. The drought caused a severe food crisis across Somalia, Ethiopia and Kenya that threatened the liveliheed of 9.5. million people. The United Nations officially declared famine in two regions in the southern part of Somalia.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 11

Alternative food sources :
To meet the additional demand for food, scientists and nutrition experts have found dietary potentials in some plant products, other than the common food materials.

  1. Moringa oleifera has incredible nutritional value. Many edible parts, like fruits, seeds, leaves, flowers are rich in protein, iron, Vit. A and Vit. C. It also has great medicinal importance.
  2. Yam bean contains enough carbohydrates, dietary fibres and Vit. C. it can be consumed raw as salad or cooked, baked and even fried. Yam bean seeds contains oil.
  3. Sago is a carbohydrate rich matter, extracted from the stem of some palm trees. The granular shape is obtained by mechanical processing. It is tasty and has good nutritive value.
  4. Gum arabic is used to prepare chewing gum. Gaur gum is applied as thickener in confectionary formulations.
  5. Green gaur beans are eaten as vegetable and are used as fodder.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 10.
Discuss the causes of world food problem.
Answer:
Causes of world food problem :
The main causes of world food problem are-
1. Increase in price of food: For the last three decades, the price of food has been it globally. Due to high price rise, people of developing countries are facing serious prob

2. Old method of farming: The practice of conventional farming like monoculture (without crop rotation), using of low yielding seed varieties, using of chemical fertilizers, farming without soil testing and lack of co-ordination between farmers and marketing sectors are the main reasons of food problems in developing countries.

3 Climatic change and natural calamities: Scarcity of rainfall or excessive rain may affect the production rate. Natural calamities, like flood or drought, also reduces the productivity of food throughout the world.

4. Erosion of soil and soil pollution: Soil erosion reduces the land, available for cultivation. Extensive use of chemical fertilizer reduces soil fertility and productivity. This is another cause of food problem.

5. Population explosion: On an average, 80 million people are born every year. But yearly production of food does not always reach that level to feed those new mouths. Therefore, increase in total number of population also increase food scarcity.

Question 11.
Classify the resources of energy on the basis of use. Mention the importance of conservation of energy resources. 3+2
Answer:
Classification of energy resources :
On the basis of use, energy resources can be classified into two types, which are mentioned below.
1. Conventional energy resources: Conventional energy resources are those which have been traditionally used for many years. These resources are also widely used at present and likely to be depleted. Example-Coal, Petroleum, Natural gas, Hydel power.

2. Non-conventional energy resources: Non-conventional energy resources are alternate energy resources to the conventional energy resources which are being considered to be used on large scale. The conventional energy resources are likely to be depleted in about 50-60 years and non-conventional energy resources should be fully developed by then to meet the energy requirement. Example-Solar energy, Wind energy, Geothermal energy, Tidal power, Biogas etc.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use 12

Importance of conservation of energy resources :

  1. Energy is of the basic needs of life, therefore resources of energy must be conserved.
  2. The conventional resources of energy, especially coal and petroleum are non-renewable, therefore they must be conserved for future generation.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 12.
Mention three basic steps towards conservation of energy resources. Mention the different uses of energy. 2+3
Answer:
Basic steps towards conservation of energy resources –
Steps towards conservation of energy resources are as follows-

  • Thermal power generation is to be regulated to conserve coal.
  • Conventional sources of energy are to be replaced by nonconventional energy sources as far as practiceable.
  • Misuse and wastage of energy resources must be cut down substancially.

Different uses of energy :
Energy requirements in different purposes are –
1. Domestic use: In rural areas, wood, coal and kerosene oil are utilized for heating and lighting purpose. In urban areas, energy is used for cooking, lighting rooms, heating, cooling, running electronic gadgets, washing machines, dishwasher, vacuum cleaners, water suction pumps etc.

2. Commercial use: In commercial buildings, such as shops, malls, hotels and restaurants, energy is used for lighting, cooling, heating and running utility gadgets.

3. Industrial use: In industries, coal, oil and natural gas are used for heating, burning and melting purposes. Lighting and running machines depend upon electrical energy.

4. Use in transport: Most of the vehicles, ranging from motor-bikes to aeroplanes, motor-boats to huge ships, run by petroleum based fuels.
Nowadays atomic energy is used to run huge submarines and aircraft carriers.

WBBSE Class 9 Life Science Solutions Chapter 5.2 Natural Resources and its Sustainable Use

Question 13.
Mention the methods of energy conservation in daily life.
Answer:
Method of energy conservation in daily life –
Energy can be consumed to a large extent in daily life by the following measures –
1. Lighting: Walls to be painted in lighter shade. Lamps should be kept dust free. Incandescent bulbs needs to be replaced with CFL to LED lamps. Electronic chokes be used instead of copper chokes.

2 Fans: Fans to be switched off before leaving room. Electronic regulators be fitted.

3. Electric iron: Ironing is to be done at right temperature. Sprayer is to be used for moistening.

4. Kitchen appliances: Grinders should be used for wet grinding. Machines are not to be run in over or under-load condition. Door of micro-oven is not to be opened frequently to check food. Flat bottom pans are to be used for induction oven.

5. Gas oven: Cooking should be done in regulated flame. Pressure cookers are to be used as much as possible. Pans to be kept covered while cooking. Before cooking items to be allowed to reach room temperature after taking out of refrigerator.

6 Water heater: Solar water heaters to be used replacing electric water heater

7. Electronic devices: Before leaving room even for short intervals, TV and audio systems should be turned off.

8. Computers: Computer monitor to be turned off during long time downloading.

9. Refrigerator: Star-rated energy saver models are to be used. Frequent opening of the door should be avoided. Door padding should be air-tight.

10. Washing machines: Washing machines should be run in full load condition at optimum water level. Perfect water and detergent quantity should be maintained.

11. Air conditioners: Energy saving star-rated equipments are to be installed and to be selected according to cooling capacity and room size. Outdoor unit is to be fitted in shady place. Filters be cleaned regulatory. Doors and windows of the room are to be sealed perfectly.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 1.3D Classification of Kingdom Animalia offer valuable context and analysis.

WBBSE Class 9 Science Chapter 1.3D Question Answer – Classification of Kingdom Animalia

Very Short Questions and Answers : (1 mark for each question)

Question 1.
In tripioblastic animals, which germinal layer is present in between ectoderm and endoderm?
Answer:
In triploblastic animals, mesoderm layer is present in between ectoderm and endoderm.

Question 2.
Name a phylum in which mesenchyme is present in between ectoderm and endoderm?
Answer:
In phylum Porifera, mesenchyme is present between ectoderm and endoderm.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 3.
Animals of which phylum possess pseudocoelom?
Answer:
Animals of phylum Nematoda possess pseudocoelom.

Question 4.
Members of which phylum use setae or parapodia for locomotion?
Answer:
Animals of phylum Annelida use setae or parapodia for locomotion.

Question 5.
In which group of animals do you find both external and internal segmentation?
Answer:
Animals under phylum Annelida have both external and internal segmentation.

Question 6.
What is paragastric cavity?
Answer:
The cavity, present inside the body of poriferans, is called paragastric cavity.

Question 7.
What is coelenteron?
Answer:
The central tubular gastrovascular body cavity present in Cnidarians is called coelenteron.

Question 8.
What is coelom?
Answer:
Coelom is the fluid-filled cavity inside animal body surrounded by mesodermal lining.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 9.
What is haemocoel?
Answer:
Haemocoel is the blood-filled coelomic body cavity, found in arthropods and molluscs.

Question 10.
What is pseudocoeiom?
Answer:
Pseudocoelom is a body cavity, typically seen in nematodes, which is not surrounded by mesodermal lining.

Question 11.
What are setae?
Answer:
Setae are minute bristle-like structures, which earthworms and some other annelids use for locomotion.

Question 12.
What are parapodia?
Answer:
Parapodia are unjointed, lobe-like, paired locomotory organs of annelids, that project laterally from the body segments.

Question 13.
What are comb plates?
Answer:
Comb plates are eight equidistant cilliary plates, present along the meridional line of the body of the members of Ctenophora to help in locomotion.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 14.
Members of which phylum is popularly called ‘comb jelly’?
Answer:
Members of phylum Ctenophora are popularly known as ‘comb jelly’.

Question .
Animals under which phylum possess cnidoblast cells?
Answer:
Animals under phylum Cnidaria possess cnidoblast cells.

Question 16.
Members of which phylum have unsegmented body covered with thick cuticle?
Answer:
Members of phylum Nematoda have unsegmented body, covered with thick cuticle.

Question 17.
Members of which phylum have segmented body covered with thick and rigid cuticle?
Answer:
Members of phylum Arthropoda have segmented body, covered with thick and rigid cuticle.

Question 18.
Members of which phylum have metamerically segmented body covered with elastic cuticle?
Answer:
Members of phylum Annelida have metamerically segmented body covered with elastic cuticle.

Question 19.
What is metameric segmentation?
Answer: The repetition of organs and tissues at intervals along the length of the body of an animal, thus dividing the body into a linear series of similar parts or segments, is called metameric segmentation.

Question 20.
Name two phyla whose members show metameric segmentation?
Answer:
Metameric segmentation is seen in the members of Annelida and Arthropoda.

Question 21.
Which group of animals use malpighian tubules for excretion?
Answer:
Members of the class Insecta, under phylum Arthropoda, use malpighian tubules as excretory organs.

Question 22.
Which group of animals use coxal gland for excretion?
Answer:
Scorpions, under class Arachnida of phylum Arthropoda, use coxal gland for excretion.

Question 23.
Which group of animals perform excretion by green gland?
Answer:
Prawns, under class Crustacea of phylum Arthropoda, perform excretion by green gland.

Question 24.
Which group of animals perform respiration by ctenidia?
Answer:
Aquatic snails and mussels, under phylum Mollusca, perform respiration by ctenidia.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 25.
Animals under which phylum possess canal system in their body?
Answer:
Animals under phylum Porifera possess canal system in their body.

Question 26.
Animals under which phylum perform locomotion by tube feet?
Answer:
Animals under phylum Echinodermata perform locomotion by tube feet.

Question 27.
Animals under which two classes possess four-chambered heart?
Answer:
Animals under class Aves and Mammalia, possess four-chambered heart.

Question 28.
Which group of vertebrates do not possess teeth?
Answer:
Birds do not possess teeth.

Short Questions and Answers : (2 marks for each question)

Question 1.
What are diploblastic animals?
Answer:
Those animals, whose body consists of two germinal layers, i.e. ectoderm and endoderm, are known as diploblastic animals. Example – Hydra etc.

Question 2.
What are triploblastic animals?
Answer:
Those animals, whose body consists of three germinal layers, i.e. ectoderm, mesoderm and endoderm, are known as triploblastic animals. Example -Tapeworms, earthworms etc.

Question 3.
What is meant by bilaterally symmetrical animals?
Answer:
The animals, which when divided once along the central axis gives two similar halves, are called bilaterally symmetrical animals. Example – Cockroach, human etc

Question 4.
What is meant by radially symmetrical animals?
Answer:
The animals, which when divided in any plane along the central axis gives rise to unlimited number of identical halves, are called radially symmetrical animals. Example – Starfish etc.

Question 5.
What is meant by asymmetrical animals?
Answer:
The animals, which when divided along any plane of the body, does not give rise to equal halves, are called asymmetrical animals. Example-Amoeba, molluscs etc.

Question 6.
What is spongocoel?
Answer:
The single, large central body cavity of the poriferan is called spongocoel. Water enters this cavity through several tiny pores called ostia and exits through a large opening called osculum.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 7.
What is meant by canal system?
Answer:
The animals under phylum Porifera have numerous pores all over the body. Through these pores water enters into the body and flows in all direction through a network of fine canals. This is called canal system.

Question 8.
What are ostia and osculum?
Answer:
Ostia: The animals under phylum Porifera possess numerous small pores all over their body which allow water to enter the body. These tiny pores are called ostia.

Osculum: The body cavity of the poriferans opens outside through a narrow circular opening, situated at the free end of their body. This opening is called osculum.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 1

Question 9.
What is mesenchyme?
Answer:
Mesenchyme or mesohyl is a jelly-like layer with a few scattered cells and collagen fibres, present in between the two layers of cells of the body of the members of phylum Porifera and Ctenophora.

Question 10.
What is mesoglea?
Answer:
Mesoglea is a completely non-cellular jellylike layer, typically seen in between ectoderm and endoderm layer of the animals under phylum Cnidaria.

Question 11.
What is cnidoblast cell?
Answer:
Cnidoblast cell is a typical explosive epidermal cell, present in numbers on the tentacles of cnidarians. These cells carry huge secretory organelle, called nematocyst, which injects strong neurotoxin into the body of the preys and attackers.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 12.
What is nematocyst?
Answer:
Nematocyst is a typical stinging cell, present in the cnidoblast of cnidarians. This is a vesicle with a hairlike sensory process ejecting, called cnidocil, which discharges strong paralysing material to the preys and attackers.

Question 13.
What is gastrovascular cavity or coelenteron?
Answer:
The central tubular body cavity of cnidarian is called gastro vascular cavity or coelenteron. This cavity functions as both oral cavity as well as digestive cavity. It plays an important role in the digestion process of cnidarians.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 2

Question 14.
What are collobiast cells or lasso cells?
Answer:
Colloblast cells or lasso cells are a kind of adhesive cells, present typically on the tentacles of the members of phylum Ctenophora. These cells are used to capture prey during predation.

Question 15.
What is metamere or somite?
Answer:
The body of annelids are transversely divisible into a series of several similar ring-like segments. These are called somites or metameres.

Question 16.
What is cephalothorax?
Answer:
The body of the members of phylum Arthropoda is segmented into head, thorax and abdomen. But certain crustaceans, such as prawn, crab, lobster etc. have their head fused with thorax. This typical structure is called cephalothorax.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 3

Question 17.
What is mantle?
Answer:
The soft visceral organs of all molluscs remain covered with a typical muscular membrane. This is called mantle. In shelled molluscs, mantle remains just beneath the shell and secrete calcium carbonate and conchiolin, that creates the shell.

Question 18.
What is ambulacrum?
Answer:
Ambulacrum is one of the numerous equidistant radial bands, present medially along the oral side of an arm of echinoderms. It is an elongated area along which numerous tube feet protrude in two rows.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 19.
What is water-vascular system?
Answer:
In echinoderms, one ring canal and five sets of radial canals with their branches, connect with numerous tube feet and constitute a well organised vascular system. Through this, water flows within their body and helps them in locomotion, respiration and food and waste transportation. This typical circulatory system is known as water-vascular system.

Question 20.
What is notochord?
Answer:
Notochord is a rod-shaped, cartilaginous, axial supporting structure, typically possessed by all embryonic and some adult chordates. It forms the primitive axis of embryo among the chordates. It is made up of cells derived from mesoderm.

Question 21.
What is nerve cord?
Answer:
Nerve cord is a tubular structure, situated longitudinally along the dorsal side of the notochord in chordates. This is ectodermal in origin and is composed of nerve cells. In vertebrates, the anterior bulbous portion of nerve cord forms the brain and the posterior tubular portion becomes the spinal cord.

Question 22.
What are pharyngeal gill slits?
Answer:
Pharyngeal gill slits are paired pores, situated laterally at two opposite sides of the pharynx of all embryonic and several adult chordates. These pores are equipped with well-vascularised structures (gills), which act as respiratory organs that help to breath in amniotic fluid.

Question 23.
What are Protozoa?
Answer:
All the unicellular, eukaryotic, microscopic organisms, which belong to the kingdom Protista, are called Protozoa. Example-Amoeba, Paramoecium etc.

Question 24.
What are Parazoa?
Answer:
The primitive type of multicellular organisms under kingdom Animalia, having no specific tissues, organs or organ systems, are called Parazoa. Example-Sponges.

Question 25.
What are Metazoa?
Answer:
All the multicellular organisms under kingdom Animalia, having well-differentiated tissues, organs and organ systems, in order to carry out various physiological activities, are called Metazoa. Example-Sea anemones, earthworms, fishes etc.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 26.
What is Porifera?
Answer:
The phylum under kingdom Animalia, whose members possess body, composed of two layers and numerous pores and complex canal system, but lack true tissues, is called Porifera. ExampleScypha, Sycon, Spongilla etc.

Question 27.
What is Cnidaria?
Answer:
The phylum under kingdom Animalia, whose members are the diploblastic animals having a central body cavity with a single opening and tentacles equipped with stinging cnidoblast cells, is called Cnidaria. Example-Aurelia aurita (jellyfish), Metridium sp. (sea anemone) etc.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 4

Question 28.
What is Ctenophora?
Answer:
The phylum under kingdom Animalia, whose members are marine, diploblastic, acoelomate, bisexual, having biradially symmetrical body and eight equidistant comb-like meridional cilliary plates along the body surface, is called Ctenophora. Example-Hormiphora, Beroe etc.

Question 29.
What is Platyhelminthes?
Answer:
The phylum under kingdom Animalia, whose members are triploblastic, bilaterally symmetrical animals with acoelomate, dorsiventrally flat body is called Platyhelminthes. Example-Planaria (flatworm), Taenia (tapeworm), Fasciola (liver fluke) etc.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 5

Question 30.
What is Nematoda or Nemathelminthes or Ascheiminthes?
Answer:
The phylum under kingdom Animalia, whose members are triploblastic, with unsegmented, tubular, pseudocoelomic and bilaterally symmetrical body is called Nematoda or Nemathelminthes or Aschelminthes. ExampleAscaris (round worm), Wuchereria (filarial worm) etc.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 31.
What is Annelida?
Answer:
The phylum under kingdom Animalia, whose members are triploblastic, having true coelome and body transversely segmented into a number of ring-shaped somites or metameres, is called Annelida. Example-Pheretima (earthworm), Hirudinaria (leech) etc.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 6

Question 32.
What is Arthropoda?
Answer:
The phylum under kingdom Animalia, whose members are triploblastic, having bilaterally symmetrical body, covered with chitinous exoskeleton and paired jointed appendages, is called Arthropoda. Example-Palaemon (prawn), Periplaneta (cockroach) etc.

Question 33.
What is Mollusca?
Answer:
The phylum under kingdom Animalia, whose members are triploblastic, coelomate, asymmetric or bilaterally symmetrical, having soft, unsegmented body, with visceral organs covered by a typical muscular membrane named mantle and the entire body covered with hard calcareous shell, is called Mollusca. Example-Pila (apple snail), Achatina (garden snail) etc.

Question 34.
What is Echinodermata?
Answer:
The phylum under kingdom Animalia, whose members are triploblastic, coelomate, pentaradially symmetrical, with numerous spines or ossicles on skin and unique water-vascular system in the body, is called Echinodermata. Example-Asterias (starfish), Cucumaria (sea cucumber) etc.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 7

Question 35.
What is Chordata? Give example.
Answer:
The phylum under kingdom Animalia, whose members are diploblastic, coelomate, bilaterally symmetrical, which, at any phase of their life cycle possess notochord, dorsal tubular nerve cord, pharyngeal gill-slits and a post anal tail, is called Chordata. Example-Shark, toad, lizards, birds, mammals, etc.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 36.
How many sub-phyla are there under phylum Chordata? Name them.
Answer:
There are three sub-phyla under phylum Chordata. They are-Urochordata, Cephalochordata and Vertebrata.

Question 37.
What is Protochordata?
Answer:
The animals under phylum Chordata, in which notochord is not replaced by vertebral column, are called protochordates. The group which consists of these animals, is called Protochordata. Members of the sub-phyla Urochordata and Cephalochordata belong to this group.

Question 38.
What is Hemichordata? Give example.
Answer:
The phylum under kingdom Animalia, whose members are triploblastic, coelomate, with worm-like body divisible into proboscis, collar and trunk, having a dorsal tubular nerve cord and a number of paired pharyngeal gill slits, is called Hemichordata. ExampleBalanoglossus, Saccoglossus etc.

Question 39.
What is Urochordata or Tunicata?
Answer:
The sub-phylum under phylum chordata, the body of whose members is covered with a thin and transparent coat or tunic and their larvae possess the notochord restricted at the tail region, is called Urochordata or Tunicata. ExampleAscidia, Doliolum, Salpa etc.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 8

Question 40
What is Cephalochordata or Acrania?
Answer:
The sub-phylum under phylum Chordata whose members are free-swimming, marine, having small lanceolate body and a well developed notochord extending from head to tail, is called Cephalochordata or Acrania. ExampleBranchiostoma, Asymmetron etc.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 41.
What is Vertebrata?
Answer:
The members of phylum Chordata, which possess a cranium, vertebral column and a welldeveloped endoskeleton, are called vertebrates and the sub-phylum is called Vertebrata. Example-Fishes, toads, dogs etc.

Question 42.
What is Agnatha?
Answer:
The vertebrates, which have a mouth without jaws, belong to a superclass called Agnatha. Example-Petromyzon (lamprey) etc.

Question 43.
What is Cyclostomata?
Answer:
The vertebrates, which have a round, jawless suctorial mouth, cartilaginous endoskeleton and a single nostril, belong to the class Cyclostomata. Example-Myxine (hagfish).

Question 44.
What is Gnathostomata?
Answer:
The vertebrates, whose mouth is guarded by a pair of jaws, having bony endoskeleton and two external nostrils, belong to a super-class called Gnathostomata. Example-Sharks, toads, mammals etc.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 45.
What is Chondrichthyes or Elasmobranchii?
Answer:
The class under kingdom Animalia, which includes jawed vertebrates, having cartilaginous endoskeleton, placoid scales on skin, mouth at the ventral side of the head and heterocercal or unevenly lobbed tail fin, is called Chondrichthyes or Elasmobranchii. Example-Scoliodon (shark), Dasyatis (stingray).
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 9

Question 46
What is Osteichthyes or Teleostomi?
Answer:
Osteichthyes or Teleostomi is a class under kingdom Animalia, which includes jawed vertebrates, having bony endoskeleton, paired gills covered with operculum, anteriorly placed mouth and homocercal or evenly lobbed tail fin. Example-Labeo rohita (rohu fish), Catla catla (catla fish) etc.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 10

Question 47.
What is Amphibia?
Answer:
Amphibia is a class under kingdom Animalia, which includes cold-blooded vertebrates, with bony endoskeleton, which perform reproduction, spend larval life in aquatic environment but on maturity spend most of their life on land, have their body covered with naked, moist glandular skin and have a three-chambered heart. Example-Duttaphrynus (toad), Rana (frog) etc.

Question 48.
What is Reptilia?
Answer:
Reptilia is a class under kingdom Animalia, which includes cold-blooded vertebrates, whose body is covered with dry epidermal scales or scutes, have pentadactyl limbs with clawed digits (exception snakes) and perform respiration with the help of lungs. Example-Calotes (garden lizard), Naja (cobra) etc.

Question 49.
What is Aves?
Answer:
Aves is a class under kingdom Animalia, which includes warm-blooded vertebrates, whose body is covered with feathers, jaws modified into beaks, fore limbs modified into wings and have four-chambered heart. Example-Corvus (crow), Pavo (peacock) etc.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 50.
What is Mammalia?
Answer:
Mammalia is a class under kingdom Animalia, which includes warm-blooded vertebrates having body hair, a pair of pinnae at two sides of the head and the female members possess mammary glands to feed milk to their offsprings. Example-Canis (dog), Felis (cat) etc.

Question 51.
Which animals are called poikilothermic or cold-blooded animals?
Answer:
Body temperature of certain animals increases and decreases according to the rise and drop of environmental temperature. These animals are called poikilothermic or cold-blooded animals. Example-Fishes, amphibians and reptiles.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 52.
Which animals are called endothermic or homoeothermic or warm-blooded animals? Give examples.
Answer:
Body temperature of certain animals does not fluctuate with the change in environmental temperature. These animals are called endothermic or homoeothermic or warm blooded animals. Example-Birds and mammals.

Long Questions and Answers : (5 marks for each question)

Question 1.
Schematically represent the classification of animal kingdom with one example each.
Answer:
Schematic representation of the classification of animal kingdom.
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 11

Question 2.
Mention the identifying features of phylum Porifera. Give two examples with scientific names.
Answer:
Identifying features of phylum Porifera
The identifying features of phylum Porifera are as follows-

  • Body is multicellular, without well-developed tissue system.
  • Body is arranged in two layers and jelly-like mesenchyme is present in between these two layers.
  • Exoskeleton is hard and rigid, made up of calcium or silicon-rich cells, called spongin fibres or spicules.
  • One large aperture, called osculum is present at the upper end of the body. There are numerous tiny pores, called ostia, spreaded all over their body.
  • Water flows continuously in the body through pores, interconnected canals and chambers.

Example with scientific names:
Two examples of the members of phylum Porifera are Neptune’s cup (Poterion neptuni) and freshwater sponge (Spongilla lacustris).

Question 3.
Mention the identifying features of phylum Cnidaria. Give two examples with scientific names.
Answer:
Identifying features of phylum Cnidaria

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 12
The identifying features of phylum Cnidaria are as follows-

  • Members of this group live in water.
  • They have a soft diploblastic body, made up of ectoderm and endoderm. In between these two layers, an acellular jelly-like mesoglea is present.
  • Body radially or biradially symmetrical, has a gastrovascular cavity called coelenteron. This cavity has a single opening that is surrounded by tentacles.
  • Typical stinging cells, called cnidoblasts, are present on the tentacles, equipped with a special stinging structure called nematocyst, which is used to capture prey and for self-defence.

Example with scientific names:
Two examples of the members of phylum Cnidaria are hydra (Hydra viritlis) and jellyfish (Aurelia aurita).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 4
Mention the identifying features of phylum Ctenophora. Give two examples.
Answer:
Identifying features of phylum Ctenophora
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 13
The identifying features of phylum Ctenophora are as follows-

  • Body is diploblastic, made up of ectoderm and endoderm and bi-radially symmetrical. In between ectoderm and endoderm, a layer of jelly-like substance called mesenchyme is present.
  • Body distinguishable into oral and aboral ends. The aboral end consists of a sensory structure, called statocyst.
  • Eight quidistant longitudinal ciliary plates or comb plates are present on the body that help in locomotion.
  • Typical adhesive cells, called colloblast cells or lasso cells are present in the tentacles. These colloblast cells help in capturing prey during predation.

Example of Ctenophores
Two examples of the members of phylum Ctenophora are Hormiphora plumosa and Beroe forskalii.

Question 5.
Mention the identifying features of phylum Platyhelininthes. Give two examples with scientific names.
Answer:
Identifying features of phylum Platyheiminthes
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 14
The identifying features of phylum Platyhelminthes are as follows-

  • Body is dorsiventrally flat, so are called flatworms and externally covered by syncytial membrane. Their body is bilaterally symmetrical.
  • Body wall is composed of three germinal layers-ectoderm, mesoderm and endoderm. Hence, they are triploblastic.
  • Body cavity or coelom is absent. Body consists of a distinct head region and a prominent sucker at the mouth.
  • Except reproductive system, other organ systems are not well developed. Excretion occurs by flame cells or protonephridia.
  • All members of this group are hermaphrodite, i.e., bisexual.
  • They may be free-living or parasitic.

Example with scientific names
Two examples of the members of phylum Platyhelminthes are tapeworm (Taenia solium) and liver fluke (Fasciola hepatica).

Question 6.
Mention the identifying features of phylum Nemathelminthes or Nematoda. Give two examples with scientific names.
Answer:
Identifying features of phylum Nemathelminthes or Nematoda
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 15
The identifying features of the phylum Nemathelminthes are as follows-

  • Body is bilaterally symmetrical, long and cylindrical.
  • They are triploblastic, i.e., body wall composed of three germinal layers-ectoderm, mesoderm and endoderm.
  • Body is unsegmented and is covered with thick cuticle.
  • A very narrow, fluid-filled body cavity or pseudocoelom is present. Organ systems are poorly developed.
  • Members of this group are unisexual, i.e., with separate male and female individuals.

Example with scientific names:
Two examples of the members of phylum Nematoda are filarial worm (Wuchereria bancrofti) and hookworm (Ancylostoma duodenale).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 7.
Mention the identifying features of phylum Annelida. Give two examples with scientific names.
Answer:
Identifying features of phylum Annelida
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 16
The identifying features of phylum Annelida are as follows

  • Body is composed of several ring-like segments called metameres or annuli. Hence, they are named annelids.
  • Body is bilaterally symmetrical and triploblastic, i.e.body wall divided into ectoderm, mesoderm and endoderm.
  • True body cavity or coelom is present. Organs are well differentiated.
  • The annelids use setae and parapodia for locomotion.
  • Each body segment bears a pair of nephridia, which act as excretory organs.

Example with scientific names
Two examples of the members of phylum Annelida are earthworm (Pheretima posthuma) and sand worm (Nereis virens).

Question 8.
Mention the identifying features of phylum Arthropoda. Give two examples with scientific names.
Answer:
Identifying features of phylum Arthropoda
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 17
The identifying features of phylum Arthropoda are as follows –

  • Body is bilaterally symmetrical and externally segmented.
  • The organisms have paired jointed appendages for locomotion.
  • Body wall composed of ectoderm, mesoderm and endoderm, i.e., they are triploblastic.
  • Body generally differentiated into head, thorax and abdomen. In some cases, head and thorax fuse together, forming cephalothorax.
  • Thick and rigid exoskeleton is present, which is made up of chitin.
  • Circulatory system is open, i.e., blood flows in coelomic body cavity, which is called haemocoel.

Example with scientific names
Two examples of the members of phylum Arthropoda are cockroach (Periplaneta americana), housefly (Musca domestica).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 9.
Mention the identifying features of phylum Mollusca. Give two examples with scientific names.
Answer:
Identifying features of phylum Mollusca
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 18
The identifying features of phylum Mollusca are as follows-

  • Body is soft, bilaterally symmetrical, unsegmented and muscular.
  • Body of most of the members are enclosed within a hard caicareous shell, made up of calcium carbonate.
  • Visceral mass remains covered with a muscular membrane, called mantle.
  • They have reduced body cavity and open circulatory system.
  • Body bears kidney-like organs for excretion. They perform respiration by a single or a pair of gill-like organs present within pulmonary sac or by means of ctenidia.
  • A special apparatus, called radula, is present at the base of mouth. It bears rows of chitinous teeth, which help in scrapping or cutting food.
  • Creeping members of this phylum have muscular foot and swimming members have undulating membrane for lacomotion.

Example with scientific names
Two examples of the members of phylum Mollusca are garden snail (Achatina fulica) and squid (Loligo vulgaris).

Question 10.
Mention the identifying features of phylum Echinodermata. Give two examples with scientific names.
Answer:
Identifying features of phylum Echinodermata
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 19
The identifying features of phylum Echinodermata are as follows-

  • Body is triploblastic, i.e., body wall made up of ectoderm, mesoderm and endoderm and body is pentaradially symmetrical.
  • Body differentiated into oral and aboral surfaces.
  • Body surface bears numerous spines and their endoskeleton consists of hard, calcareous ossicles, that are made up of calcium carbonate.
  • Oral surface of the body has five radial ambulacra with distinct ambulacral grooves.
  • They have a proper coelomic cavity and wellorganised water-vascular system that is used for circulation.
  • Numerous tube feet are present on either side of the ambulacral grooves, which help in locomotion.

Example with scientific names
Two examples of the members of phylum Echinodermata are starfish (Asterias rubens), and sea cucumber (Cucumaria frondosa).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 11.
Mention the Identifying features of phylum Hemichordata. Give two examples.
Answer:
Identifying features of phylum Hemichordata
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 20
The identifying features of phylum Hemichordata are as follows-

  • Members of this group are Balanoglossus soft bodied, coelomate, worm-like, marine animals.
  • Body is divided into proboscis, collar and trunk.
  • Paired pharyngeal gill slits are present in the trunk.
  • They are devoid of endoskeleton and notochord.
  • The nerve cord is dorsally placed, which is rod-like in most members, but hollow in few.
  • A small diverticulum is present near oesophagus, called stomochord, which is a flexible hollow tube that helps to communicate with oral cavity.
  • They possess an independent larval stage, named tornaria larva, at initial stage of their life cycle.

Examples of hemichordates
Two examples of hemichordates are Balanoglossus gigas and Saccoglossus sp.

Question 12.
Mention the Identifying features of phylum Chordata. Give two examples.
Answer:
Identifying features of phylum Chordata
The identifying features of phylum Chordata are as follows-

  • A tubular nerve cord is present at dorsal side of the body.
  • Below the dorsal tubular nerve cord, the animals possess a rod-shaped supporting structure, called notochord. It remains throughout their life or at least during embryonic stage.
  • Paired pharyngeal gill slits are present throughout or, at certain period of their life cycle.
  • All members have a post anal tail or at least some remains of it.
  • The members under this phylum possess closed circulatory system.

Example of chordates
Two examples of chordates are Branchiostoma lanceolatum and Homo sapiens sapiens.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 13.
Distinguish between chordates and non-chordates.
Answer:
Differences between chordates and non-chordates

Features Chordates Non-chordates
1. Notochord Present throughout or at certain stage of life cycle Completely absent
2. Nerve cord Tubular structure, present at the dorsal side of the body Thread-like structure, present at the ventral side of the body
3. Vertebral column Present in most members Completely absent
4. Skull Present and made up of bones and cartilages Absent
5. Circulatory system Closed circulatory system with arteries, veins and capillaries Open circulatory system with arteries and veins, but capillaries are absent

Question 14.
Mention the identifying features of sub-phylum Urochordata. Give two examples.
Answer:
Identifying features of sub-phylum Urochordata
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 21
The identifying features of sub-phylum Urochordata are as follows

  • Sac-like soft body of the members is covered by a membrane called tunic.
  • Paired pharyngeal gill slits are present in adults. The pharyngeal region is surrounded by a membrane-bound cavity, called atrium.
  • Notochord and nerve chord present during larval stage.
  • Free-swimming tadpole stage is observed during the life cycle of the organisms. They undergo retrogressive metamorphosis by losing notochord and nerve cord on maturity.

Example of urochordates
Two examples of urochordates are Ascidia mentula and Doliolum denticulatum.

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 15.
Mention the identifying features of sub-phylum Cephalochordata. Give two examples.
Answer:
Identifying features of sub-phylum Cephalochordata
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 22
The identifying features of sub-phylum Cephalochordata are as follows-

  • This sub-phylum includes small fish-like animals with indistinct head. Body is bilaterally symmetrical, triploblastic and with coelomic body cavity.
  • Notochord is well developed, which contracts and expands and extends from head to tail.
  • Dorsal tubular nerve cord and paired pharyngeal gill slits are present.
  • A typical ciliated groove, called endostyle, is present at the ventral wall of pharynx.
  • Oral opening is laterally guarded by two flap-like structures, called oral hoods, with ciliated edge.

Example of cephalochordates
Two examples of cephalochordates are Branchiostoma lanceolatum and Asymmetron inferum.

Question 16
Mention the identifying features of sub-phylum Vertebrata or Craniata. Give two examples with scientific names.
Answer:
Identifying features of sub-phylum Vertebrata or Craniata
The identifying features of sub-phylum Vertebrata are as follows-

  • Members of this group are bilaterally symmetrical, triploblastic and with coelomic body cavity.
  • Notochord is replaced by a true vertebral column. Body possesses internal skeleton, made up of bones and cartilage.
  • Brain remains protected inside cranium.
  • Dorsal tubular nerve cord emerges from base of the brain and passes through the vertebral column.
  • Two pairs of joint limbs present, which help in locomotion.

Example with scientific names
Two examples of the members of sub-phylum Vertebrata are rohu fish (Labeo rohita) and cat (Felis domesticus).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 17.
Mention the identifying features of super-class Agnatha with two examples. Mention the identifying features of super-class Gnathostomata with two examples.
Answer:
Identifying features of super-class Agnatha
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 23
The identifying features of super-class Agnatha are as follows-

  • Body is elongated, with cartilaginous endoskeleton.
  • Suctorial mouth is present without any jaw.
  • Only a single external nostril is present.
  • A number of pharyngeal gill slits are present along the two opposite sides of the body.

Example – Two examples of the members of super-class Agnatha are lamprey (Petromyzon marinus) and hagfish (Myxine glutinosa).

Identifying features of super-class Gnathostomata
The identifying features of super-class Gnathostomata are as follows-

  • The mouth of the animals under this super-class is guarded by a pair of jaws.
  • They have two external nostrils.
  • Endoskeleton is made up of either bone or cartilage

Example- Two examples of the members of super-class Gnathostomata are shark (Scoliodon sorrakowah) and crocodile (Crocodylus porosus).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 18.
Mention the identifying features of class Cyclostomata. Give two examples with scientific names.
Answer:
Identifying features of class Cyclostomata
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 24
Cyclostomata is the only class under super-class Agnatha. Its characteristic features are as follows:

  • The animals under this class are cold-blooded. Mouth has no jaw. Oral opening has a circular sucker, which is guarded by papillae or small tentacles.
  • One medial external nostril is present.
  • Body is long, cylindrical, tapering towards the tail.
  • The members do not have distinct stomach or any appendages.
  • Fertilisation, as well as development, both are external.
  • They possess unpaired fins and do not have body scales.
  • Skull and endoskeleton, both are cartilaginous.
  • Heart is two-chambered, 6-14 pairs of gills present in sac.

Example with scientific names
Two examples of the members of class Cyclostomata are lamprey (Petromyzon marinus) and hagfish (Myxine glutinosa).

Question 19
Mention the identifying features of class Chondrichthyes. Give two examples with scientific names.
Answer:
Identifying features of class Chondrichthyes
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 25
The identifying features of class Chondrichthyes are as follows-

  • The animals under this class Shark are cold-blooded and bilaterally symmetrical.
  • Members of this group have streamlined body and cartilaginous endoskeleton.
  • Body is covered with minute placoid scales.
  • About 5-7 pairs of gill slits present at the lateral side of the body and are without operculum.
  • Mouth present at the ventral side of the head.
  • Body has paired and unpaired fins, with fin rays. Air bladder typically absent.
  • They possess heterocercal tail, i.e., with two unequal lobes. Anal fins of male form claspers, which help to deposit sperms.

Example with scientific names
Two examples of the members of class Chondrichthyes are shark (Scoliodon sorrakowah) and sawfish (Anoxypristis cuspidata).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 20.
Mention the identifying features of class Osteichthyes. Give two examples with scientific names.
Answer:
Identifying features of class Osteichthyes
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 26
The identifying features of the class Osteichthyes are as follows

  • The animals under this class are bilaterally symmetrical and are cold-blooded animals.
  • They have streamlined body covered with ganoid, cycloid or ctenoid scales.
  • Their endoskeleton and fin rays are made up of bones.
  • Four pairs of gills present in gill chambers on either side of head. Each gill Rohu fish chamber remains covered with a bony plate, called operculum.
  • Five pairs of gill arches and one pair of external gill slits present.
  • They have paired or unpaired fins, with bony fin rays.
  • Tail fin is homocercal with identical lobes.
  • A typical swim bladder is present in the body.

Example with scientific names
Two examples of the members of class Osteichthyes are rohu fish (Labeo rohita) and catla fish (Catla catla).

Question 21.
Mention the identifying features of class Amphibia. Give two examples with scientific names.
Answer:
Identifying features of class Amphibia
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 27
The identifying features of class Amphibia are as follows-

  • The animals belonging to this class are cold-blooded animals.
  • Body is differentiated into head and trunk, without distinct neck.
  • Body is covered with naked, moist, glandular skin without scales.
  • Larvae live in water and respire with external gills. Adults are terrestrial and respire with lungs, but apart from this, skin and buccopharyngeal cavity also participate in respiration.
  • Forelimbs have four and hind limbs have five digits each. The digits are without claws.
  • They have three-chambered heart, with two auricles and one ventricle.

Example with scientific names
Two examples of the members of class Amphibia are toad (Duttaphrynus melanostictus) and frog (Rana tigrina).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 22.
Mention the identifying features of class Reptilia. Give two examples with scientific names.
Answer:
Identifying features of class Reptilia
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 28
The identifying features of class Reptilia are as follows –

  • The animals under this class are cold-blooded animals.
  • Body is covered with large dermal plates or dry epidermal scales, called scutes.
  • They perform locomotion by crawling.
  • Each of the fore and hind limbs have five clawed digits. (exception-snakes are limbless).
  • Body is distinctly divisible into head, neck, trunk and tail. Cloaca is present transversely near the base of the tail.
  • They generally have three chambered heart, with two auricles and a partially divided ventricle (exception – crocodile has four-chambered heart with completely divided ventricle).

Example with scientific names
Two examples of the members of class Reptilia are garden lizard (Calotes versicolor) and crocodile (Crocodylus porosus).

Question 23
Mention the identifying features of class Aves. Give two examples with scientific names.
Answer:
Identifying features of class Aves
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 29
The identifying features of the class Aves are as follows-

  • The animals belonging this class are warm-blooded animals.
  • Body is spindle-shaped and covered with feathers.
  • Forelimbs are modified into wings.
  • Their bones are hollow due to the presence of air cavities. This helps to reduce their weight and help in flying.
  • Besides lungs, they have 9 air sacs, which help in flight.
  • Urinary bladder, rectum and right ovary absent in order to reduce body weight.
  • Teeth completely absent and jaws are modified into beaks.
  • They have four-chambered heart with two auricles and two ventricles.

Example with scientific names
Two examples of the members of class Aves are crow (Corvus splendens) and pigeon (Columba livia).

WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia

Question 24
Mention the identifying features of class Mammatia. Give two examples with scientific names.
Answer:
Identifying features of class Mammalia
WBBSE Class 9 Life Science Solutions Chapter 1.3D Classification of Kingdom Animalia 30
The identifying features of class Mammalia are as follows-

  • The animals under this class are warm-blooded animals and their bodies are bilaterally symmetrical.
  • Body is covered with hair. Sweat and sebaceous glands are present in the skin.
  • The female members of this group have milk-producing mammary glands, for nourishing their young ones.
  • A pair of external ears or pinnae is present on either side of the head.
  • Respiration occurs by a pair of lungs.
  • They have two pairs of limbs, used for locomotion, digging, holding or feeding.
  • They are viviparous animals, i.e., give birth to young ones.
  • Heart is four-chambered with two auricles and two ventricles and has left aortic arch.

Example with scientific names
Two examples of the members of class Mammalia are man (Homo sapiens sapiens) and deer (Axis axis).

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 1.3C Classification of Kingdom Plantae offer valuable context and analysis.

WBBSE Class 9 Science Chapter 1.3C Question Answer – Classification of Kingdom Plantae

Very Short Questions and Answers : (1 mark for each question)

Question 1.
Members of which group of plants are not divisible into roots, stems and leaves?
Answer:
Members of thallophyta are not divisible into roots, stems and leaves.

Question 2.
Name an alga which has spirally coiled chloroplast In its cells.
Answer:
Spirogyra is an alga, has spirally coiled chloroplast in its cells.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 3.
Name a filamentous alga having prokaryotic cells.
Answer:
Nostoc is a filamentous alga, having prokaryotic cells.

Question 4.
Name a colony-forming alga.
Answer:
Volvox is a colony-forming alga.

Question 5.
Name a unicellular alga, which is now treated as a protist.
Answer:
Chlamydomonas is a unicellular alga, which is now treated as a protist.

Question 6.
What is the fine, branched, colourless, filamentous structure of a fungus called?
Answer:
The fine, branched, colourless, filamentous structure of a fungus is called mycelium.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 7.
What are the filaments of a fungal mycelium known as?
Answer:
The filaments of a fungal mycelium are known as hyphae.

Question 8.
What is the name of the fungal component of a lichen?
Answer:
The fungal component of a lichen is called mycobiont.

Question 9.
What is the name of the algal component of a lichen?
Answer:
The algal component of a lichen is called phycobiont.

Question 10.
Which type of bryophytes form velvety thallus on moist soil?
Answer:
Liverworts form velvety thallus on moist soil.

Question 11.
What is the name of the erect portion of moss?
Answer:
The erect portion of moss is called gametophore.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 12.
What is the name of the stem-like portion of a moss?
Answer:
The stem-like portion of a moss is called caulid.

Question 13.
What is the name of the fine root-like structure of a moss?
Answer:
The fine root-like structure of a moss is called rhizoid.

Question 14.
What does the rhizoid of a moss do?
Answer:
Rhizoid of a moss absorbs water from the soil and affix the plant body to the soil.

Question 15.
Which type of plants possess leaves, stems and roots but do not develop flower and fruit?
Answer:
Ferns possess leaves, stems and roots but do not develop flower and fruit.

Question 16.
Which plants possess ramenta on their stems and the petioles of leaves?
Answer:
Ferns posses ramenta on their stems and the petioles of leaves.

Question 17.
Name a plant in which aerial part is comprised of pileus and stipe.
Answer:
Aerial part of Agaricus is comprised of pileus and stipe.

Question 18.
What are the wart-like structures below the leaflets of Dryopteris called ?
Answer:
The wart-like structures below the leaflets of Dryopteris are called sori.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 19.
Members of which division of plants are known as amphibious plants?
Answer:
Plants under division bryophyta are known as amphibious plants.

Question 20.
In which division of plants, seeds develop without formation of fruits?
Answer:
In gymnosperms, seeds develop without formation of fruits.

Question 21.
Which type of plant body is seen amongst ferns?
Answer:
Sporophytic plant body is seen amongst ferns.

Question 22.
What is the name of the symbiotic association of fungi and the roots of higher vascular plants?
Answer:
The symbiotic association of fungi and the roots of higher vascular plants is known as mycorrhiza.

Question 23.
Which division of non-flowering plants possess vascular system?
Answer:
Plants under division pteridophyta are nonflowering plants, which possess vascular system.

Question 24.
In which group of plants usually many embryos are formed in a single seed?
Answer:
In gymnosperms, usually many embryos are formed in a single seed.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 25.
Which group of plants always show tap root system?
Answer:
Dicotyledonous plants always show tap root system.

Short Questions and Answers : (2 marks for each question)

Question 1.
What is meant by algae?
Answer:
The simplest form of autotrophic, aquatic plants, with thallophytic body, made up of mainly eukaryotic cells, without any tissue system and having unicellular sex organs, are called algae. Example-Spirogyra sp., Chara sp.

Question 2.
What is thallophyta?
Answer:
Thallophyta is a plant group, that includes those plants having flat thallus-like body, which are not divisible into root, stem and leaf. Example-Algae.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 3.
What are bryophytes?
Answer:
Bryophytes are simple non-flowering plants without true roots, stems, leaves and vascular tissues. They grow in moist soil but perform fertilisation in water and maintain gametophytic generation throughout the major part of their life cycle. Example-Pogonatum sp., Sphagnum sp.
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 1

Question 4.
What are pteridophytes?
Answer:
Pteridophytes are terrestrial non-flowering plants having true roots, stems, leaves and vascular tissues. They maintain sporophytic generation throughout the major part of their life cycle.
Example — Marsilea sp., Selaginella sp.
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 2
Question 5.
What are gymnospenns?
Answer:
The group of plants, in which no fruit is produced, so that the seeds remain exposed and usually many embryos form inside a seed, are called gymnosperms or naked-seeded plants, where endosperm forms before fertilisation. Example — Cycas sp., Pinas sp.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 3

Question 6.
What are anglesperms?
Answer:
The flowering plants, in which fruits develop from flowers and seeds remain within the fruits, are called angiosperms. Here, the endosperm forms after fertilisation. Example — Solanum tuberosum (potato), Malus domestica (apple).

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 7.
What is meant by dicotyledonous plants?
Answer:
The angiospermic plants, in which seeds have two cotyledons, show tap root system and have reticulate venation in leaves, are called dicotyledonous plants. Example-Mangifera indica (mango), Pisum sativum (pea).
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 4

Question 8.
What is meant by monocotyledonous plants?
Answer:
The angiospermic plants, in which seeds have only one cotyledon, show adventitious root system and have parallel venation in leaves, are called monocotyledonous plants. Example-Cocos nucifera (coconut), Triticum aestivum (wheat).

Question 9.
What are rhizoids?
Answer:
Rhizoids are branched, colourless, very fine thread-like structures growing from the base of the gametophores or the ventral side of the thallus of mosses, which help to absorb water and minerals from soil and affix the plant with the subtratum.

Question 10.
What is a gametophore?
Answer:
The gametophore is a structure, present in the gametophytic generation of mosses and ferns, which bears the male and female sex organs, known as antheridium and archegonium respectively.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 11.
What are ramenta? What is the function of ramenta?
Answer:
(i) Ramenta: Some species of ferns have several thin, brown scale or hair-like projections upon the young shoots and the petioles of leaves. These are called ramenta.
(ii) Function: Ramenta prevent the ferns from drying out by reducing the rate of transpiration in arid condition.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 5

Question 12.
What is circinate vernation?
Answer:
The manner in which immature leaves of ferns are tightly curled so that the tender growing tip of the frond remains protected within a coiled structure, is called circinate vernation. This is commonly seen in Dryopteris sp.
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 6

Long Questions and Answers : (5 marks for each question)

Question 1.
Classify plant kingdoms with the help of a chart and example.
Answer:
Classification of plant kingdom with examples
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 7

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 2.
Mention the similarities between algae and fungi. Discuss their differences.
Answer:
Similarities between algae and fungi
The similarities between algae and fungi are as follows-

  • Both are eukaryotic, unicellular or multicellular.
  • Both forms are thallophytic, that is their body is not differentiated into roots, stems and leaves.
  • Both algae and fungi have distinct cell wall outside their cells.
  • Both algae and fungi are devoid of vascular tissues.

Differences between algae and fungi

Features Algae Fungi
1. Habitat Mostly aquatic, few grow on moist soil Mostly terrestrial
2. Nutrition Mostly autotrophic All are heterotrophic, mostly saprophytic, some are parasitic
3. Photosynthetic pigments Chlorophyll and other pigments Photosynthetic pigments absent
4. Main component of cell wall Main component is cellulose Main component is chitin
5. Stored food Stored food is starch and other polysaccharides Stored food is glycogen
6. Vacuole Centrally large and few vacuoles present Small and many vacuoles present

Question 3.
Mention the similarities between bryophytes and pteridophytes. Discuss the differences between them.
Answer:
Similarities between bryophytes and pteridophytes
The similarities between bryophytes and pteridophytes are as follows-

  • Both bryophytes and pteridophytes are non-flowering plants.
  • Both show distinct gametophytic and sporophytic generations in their respective life cycles.
  • Both require water for fertilisation.
  • Both carry out asexual reproduction by means of spores.
  • The structure of male and female gametangia are alike in both bryophytes and pteridophytes. Reproductive cells are externally covered by sterile cells.

Differences between bryophytes and pteridophytes

Features Bryophytes Pteridophytes
1. Body Body differentiated into stem and leaves, true roots absent Body differentiated into true roots, stem and leaves
2. Main plant type Main plant type is gametophytic Main plant type is sporophytic
3. Vascular tissue True vascular tissues are absent Xylem and phloem are present
4. Habitat Moist soil and rocky surfaces Cool, shady but dry surfaces
5. Roots True root system absent, root-like rhizoids are present True root system is present
6. Sperms Sperms biflagellate Sperms multi flagellate

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 4.
Mention the similarities between gymnosperms and angiosperms. Write the differences between them.
Answer:
Similarities between gymnosperms and angiosperms
Similarities between gymnosperms and angiosperms are as follows—

  • Both gymnosperms and angiosperms have their bodies differentiated into true roots, stems and leaves.
  • Both the types of plants develop seeds after fertilisation.
  • In both forms, the ovules remain covered by integument.
  • Both gymnosperms and angiosperms have well-organised vascular bundle.

Differences between gymnosperms and angiosperms:

Features Gymnosperms Angiosperms
1. Nature Perennial and evergreen Annual, biennial or perennial, evergreen or deciduous
2. Vascular tissue

 

Xylem and phloem are devoid of trachea and companion cells respectively We developed xylem and phloem present
3. Flower and fruit Flowers lack ovary, therefore no fruit formation occurs Flowers have ovary, which matures into fruit
4. Seed Seeds remain exposed Seeds remain inside the fruit
5. Embryo More than one embryo originates in ovule, but only one matures Single embryo is formed in an ovule
6. Endosperm Endosperm forms before fertilisation Endosperm forms after fertilisation

Question 5.
Mention the differences between monocotyledonous and dicotyledonous plants. Write the scientific names of two monocot and two dicot plants.
Differences between monocotyledonous and dicotyledonous plants
Answer:

1. Nature Annual, mostly herbs, rarely shrubs and trees Perennial, majority are trees, but several herbs and shrubs are also present
2. Cotyledons Seed has single cotyledon Seed has two cotyledons
3. Leaves Isobilateral, with parallel venation Dorsiventral, with reticulate venation
4. Stem Generally unbranched and less woody Well-branched and mostly woody
5. Root Adventitious roots present Taproot system present
6. Vascular bundle Numerous and scattered vascular bundles in stem Few vascular bundles in stem, arranged in circles or rings

Scientific name of monocot and dicot plants
The scientific names of two inonocot plants are Oryza sativa (rice) and Zea mays (maize) and the scientific names of two dicot plants are Mangifera indica (mango) and Pisum sativum (pea)

Question 6.
Mention the main characteristic features of algae, Give two examples.
Answer:
Characteristic features of algae
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 8
The main characteristic features of algae are as follows—

  • Algae are unicellular or multicellular aquatic thallophytes.
  • These are autotrophic, i.e. they can synthesise their own food within the body, due to the presence of chlorophyll.
  • Algal cell wall is mainly composed of cellulose and pectin.
  • Algal cells have variously shaped chloroplasts, which contain photosynthetic pigments and stored food like starch.
  • Sub-cellular micro compartments, called pyrenoids, are present in the chloroplasts.
  • Algae perform vegetative, asexual and sexual reproduction.

Examples of algae
Two examples of algae are Spirogyra maxima and Volvox globator.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 7.
Mention the main characteristic features of bryophytes. Give two examples. Characteristic features’ of bryophytes
Answer:
The main characteristic features of bryophytes are as follows:
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 9

  • Bryophytes are green, photosynthetic and non-vascular plants.
  • Plants are either thallus-like or have indistinguishable stem-like caulid, leaf-like phyllids and rhizoids in place of roots.
  • The plant body of bryophytes is gametophytic.
  • Sporophyte depends upon the gametophyte for survival.
  • Both male and female reproductive organs are multicellular.
  • Alternation of generation is distinct and unequal, where gametophytic generation dominates over the sporophytic generation.

Examples of bryophytes
Two examples of bryophytes are Riccia fluitans and Funaria hygrometrica.

Question 8.
Mention the main characteristic features of pteridophytes. Give two examples.
Answer:
Characteristic features of pteridophytes:
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 10
The main characteristic features of pteridophytes are as follows-

  • Pteridophytes are muiticellular, non-flowering plants with vascular tissue system.
  • Vascular system is composed of xylem and Marsilea minuta phloem.
  • Vegetative body is differentiated into roots, stems and leaves.
  • The independent plant body is sporophytic.
  • Sporophylls or spore bearing leaves either arrange themselves to form cones or remain free as compound leaves.
  • Alternation of generation is distinct and unequal, where sporophytic generation dominates over the gametophytic generation.

Examples of pteridophytes:
Two examples of pteridophytes are Dryopteris filix-mas and Marsilea minuta.

Question 9.
Mention the main characteristic features of gymnosperms. Give two examples.
Answer:
Characteristic features of gymnosperms:
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 11
The main characteristic features of gymnosperms are as follows-

  • Gymnosperms are perennial sporophytic trees.
  • Body differentiated into roots, stems and leaves.
  • Leaves are of two types-dry brown scale leaves and green foliage leaves. Foliage leaves are either needle-like or compound.
  • Vascular system present but xylem and phloem are devoid of trachea and companion cells respectively.
  • Fruit absent, that is why seeds remain exposed or naked.
  • Seeds bear more than one embryo, a feature typically known as polyembryony.
  • In gymnosperms, endosperm develops before fertilisation.

Examples of gymnosperms:
Two examples of gymnosperms are Pinus roxburghii and Gnetum ula.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 10.
What is a sorus? What is cone or strobilus? Give the differences between cryptogams and phanerogams.
Answer:
Sorus
The small, kidney-shaped, wart-like structure which grows on the ventral surface of the leaflets of ferns, to hold the sporangia within it, is called sorus.
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 12

Cone or Strobilus
In most gymnosperms, a number of male or female reproductive organs or sporangia-bearing, scale-like structures arrange closely around a central axis to form a cone-shaped or oval structure. This is called cone or strobilus.

Differences between cryptogams and phanerogams:

Features Cryptogams Phanerogams
1. Seeds Do not produce seeds Produce seeds
2. Vascular system May or may not be present Always present
3. Need for water External water serves as medium External water is not required
4. Evolutionary status These are primitive type These are advanced type

Question 11.
Mention the main characteristic features of angiosperms. Give two examples.
Answer:
Characteristic features of angiosperms
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 13
The main characteristic features of angiosperms are as follows-

  • Angiosperms are either herbs, shrubs or trees.
  • Their life span varies from annual, biennial to perennial.
  • Vascular tissue system is highly developed, composed of all components of xylem and phloem.
  • Flowers develop ovary, which matures into fruit. Seeds remain protected inside the fruit.
  • Seeds may have one or two cotyledons.
  • In angiosperms, endosperm develops after fertilisation.

Examples of angiosperms
Two examples of angiosperms are Cocos nucifera and Mangifera indica.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 12.
Mention the main characteristic features of monocotyledonous plants. Give two examples.
Answer:
Characteristic features of monocotyledonous plants
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 14
The main characteristic features of monocotyledonous plants are as follows-

  • Monocots are mostly herbs, a few are trees.
  • Their life span varies from annual to perennial.
  • Their seeds have a single cotyledon.
  • Their roots are adventitious.
  • Stems are unbranched and leaves are isobilateral with parallel venation.
  • Fruit coat remains fixed with the seed coat.

Examples of monocotyledonous plants
Two examples of monocotyledonous plants are Oryza sativa and Zea mays.

WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae

Question 13.
Mention the main characteristic features of dicotyledonous plants. Give two examples.
Answer:
Characteristic features of dicotyledonous plants
WBBSE Class 9 Life Science Solutions Chapter 1.3C Classification of Kingdom Plantae 15
The main characteristic features of dicotyledonous plants are as follows-

  • Dicots are mostly trees, some are herbs and shrubs.
  • Their life span varies from annual, biennial to perennial.
  • Their seeds have two cotyledons.
  • Well developed tap root system is present in these type of plants.
  • Stems are branched and leaves are dorsiventral with reticulate venation.
  • Fruit coat and seed coat remain separate.

Examples of dicotyledonous plants
Two examples of dicotyledonous plants are Artocarpus heterophyllus and Pisum sativum.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 1.3B Five Kingdoms of Life offer valuable context and analysis.

WBBSE Class 9 Science Chapter 1.3B Question Answer – Five Kingdoms of Life

Very Short Questions and Answers : (1 mark for each question)

Question 1.
Which type of cells are found among the members of kingdom Monera?
Answer:
Members of kingdom Monera have prokaryotic cells.

Question 2.
The cell wall of the members of kingdom Monera is made up of what?
Answer:
Cell wall of the members of kingdom Monera is made up of polysaccharides and amino acids.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Question 3.
Mention the nature of cells, found among the members of kingdom Protista.
Answer:
Members of kingdom Protista have eukaryotic cells.

Question 4.
Which cell wall component is found among the members of kingdom Fungi?
Answer:
Chitin is the cell wall component found amongst the members of kingdom Fungi.

Question 5.
Which major cell wall component is found among the members of kingdom Plantae?
Answer:
Cellulose is the major cell wall component, found amongst the members of kingdom Plantae.

Question 6.
Which type of nutrition is performed by the members of kingdom Plantae?
Answer:
Members of kingdom Plantae perform autotrophic mode of nutrition.

Question 7.
Which type of nutrition is performed by the members of kingdom Fungi?
Answer:
Saprophytic or parasitic nutrition is commonly performed by the members of kingdom Fungi.

Question 8.
Which type of nutrition is performed by the members of kingdom Animalia?
Answer:
Members of kingdom Animalia perform heterotrophic mode of nutrition.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Question 9.
Which members of living world perform the role of producers in any ecosystem?
Answer:
Members of kingdom Plantae perform the role of producers in any ecosystem.

Question 10.
Which members of living world perform the role of consumers in any ecosystem?
Answer:
Members of kingdom Animalia perform the role of consumers in any ecosystem.

Question 11.
Which members of living world perform the role of decomposers in any ecosystem?
Answer:
Members of kingdom Fungi perform the role of decomposers in any ecosystem.

Question 12.
Which members of kingdom Protista typically possess two flagella?
Answer:
Among the members of kingdom Protista, dinoflagellates typically possess two flagella.

Question 13.
Members of which kingdom perform the role of producers, consumers as well as decomposers in any ecosystem?
Answer:
Members of kingdom Protista perform the role of producers, consumers as well as decomposers in any ecosystem.

Question 14.
Members of which kingdom/kingdoms cause maximum number of human diseases?
Answer:
Members of kingdom Monera, Protista and Fungi cause maximum number of human diseases.

Short Questions and Answers : (2 marks for each question)

Question 1.
Name the five kingdoms of the living world, as proposed by Whittaker.
Answer:
The five kingdoms of the living world, as proposed by Whittaker are – Monera, Protista, Fungi, Plantae and Animalia.

Question 2.
What is meant by Monera?
Answer:
The word Monera has been derived from a Greek word ‘monos’, which means ‘single’. Monera is a kingdom of the living world, which is comprised of unicellular, microscopic and very primitive type of prokaryotic organisms. Example-Bacteria, blue-green algae etc. belong to this group.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Question 3.
What is meant by Protista?
Answer:
The word Protista has been derived from a Greek word ‘protistos’, which means ‘first of all.’ Protista is a kingdom of the living world, which is comprised of unicellular, eukaryotic, microscopic organisms. Example-Amoeba proteus, Euglena viridis etc.

Question 4.
What is meant by Fungi?
Answer:
The word Fungi has been derived from a Latin word ‘fungour’, which means ‘growing fast’. Fungi is a kingdom of the living world, which comprises eukaryotic, non-chlorophyllous, spore-bearing organisms, having cells with chitin-rich cell wall and performing both sexual and asexual reproduction. Example – Mucor mucedo, Aspergillus niger.

Question 5.
What is meant by eukaryotic cells?
Answer:
The cells, which possess well-organised nucleus and membrane-bound cell organelles, are known as eukaryotic cells. Example-The cells of all higher plant and animal cells.

Question 6.
What is meant by prokaryotic cells?
Answer:
The cells, which do not possess true nucleus and membrane-bound cell organelles, are called prokaryotic cells. Example-Bacteria, Mycoplasma, blue-green algae etc.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Question 7.
Mention two disadvantages of five kingdom classification.
Answer:
Two disadvantages of five kingdom classification are as follows-

  • Different members Algae have been placed under three different kingdoms-blue-green algae under Monera, Euglena under Protista and brown algae under Plantae, which is ambiguous.
  • Virus has not been included under any of the five kingdoms.

Question 8.
Which type of organisms are placed under kingdom Plantae?
Answer:
According to five kingdom classification of the living world, all chlorophyllous, photosynthetic, eukaryotic, multicellular organisms with cellulose containing cell wall, are included under kingdom Plantae.

Long Questions and Answers : (5 marks for each question)

Question 1.
Explain the basis of five kingdom classification.
Answer:
Basis of five kingdom classification
The characteristic features, based on which Whittaker proposed his five kingdom classification, are discussed below.
1. Complexity of cellular structure: On the basis of this feature, the living world is divided into two main divisions-

  • Prokaryotes: Primitive forms without true nucleus.
  • Eukaryotes: More complex forms along with true nucleus and membrane-bound cell organelles.

2. Complexity of body structure: Based on the number of cells present in a living body, organisms are classified into two groups-

  • Unicellular: Body is made up of single cell.
  • Multicellular: Body is made up of many cells. In case of multicellular forms, the nature of tissue and tissue systems are also taken into consideration.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

3. Mode of nutrition: Living forms are classified into two main types, on the basis of their modes of nutrition. These are-

  • Autotrophs: They are photosynthetic forms capable of preparing their own food.
  • Heterotrophs: These are organisms which depend directly or indirectly on autotrophs for food.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life 1

4. Role in ecosystem: Based on their roles in ecosystem, living forms are classified into three types-

  • Producers: They synthesise their own food within their body. Mainly photosynthetic green plants belong to this group.
  • Consumers: They depend directly or indirectly on producers for food. These include all animals.
  • Decomposers: They take part in biodegradation of organic matters. Various bacteria and fungi belong to this group.

5. Phylogenetic relation: Besides morphological, anatomical, biochemical and genetic features, the evolutionary trend of different groups are equally emphasized in this type of classification.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Question 2.
Compare the features of the five different kingdoms.
Answer:
Comparative features of the five kingdoms
WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life 2

Question 3.
Mention three identifying features of kingdom Monera. Give two examples of Monera.
Answer:
Identifying features of kingdom Monera
Three identifying features of kingdom Monera are as follows-
1. Ceil and cellular organisation : Members of this kingdom are unicellular, microscopic organisms. Their cells do not contain any membrane-bound organelle and membrane-bound true. nucleus is absent (i.e. prokaryotic). Genetic material is represented by a naked circular DNA. Ribosomes and chromatophores are present. Cell wall is composed of polysaccharides and amino acids.

2. Mode of nutrition: Nutritionally these are heterotrophic (parasitic, saprophytic, symbiotic) or autotrophic. Autotrophs are either photosynthetic or chemosynthetic. Among heterotrophs, saprophytes obtain nutrients from dead and decaying organic matters. Symbionts obtain nutrition by the help of other organisms.

3. Role in ecosystem: Photosynthetic and chemosynthetic forms play the role of producers. Heterotrophs act as consumers and saprophytes act as decomposers.
WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life 3

Two examples of Monera:
Two examples of Monera are Mycobacterium tuberculosis and Escherichia coli.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Question 4.
Mention three identifying features of kingdom Protista. Give two examples of Protista.
Answer:
Identifying features of kingdom Protista:
Three identifying features of kingdom Protista are as follows-

1. Cell and cellular organisation: These are unicellular, microscopic organisms. Cells contain membrane-bound cell organelles and true nucleus (i.e. eukaryotic). Nucleus contains chromosomes, which contain genetic material.

2. Mode of nutrition: These are heterotrophic (parasitic, symbiotic) or autotrophic in nature. Parasites obtain nutrients from the body of the host. Symbionts obtain nutrition by the help of other organisms.

3. Role in ecosystem: Photosynthetic forms (autotrophs) play the role of producers. Heterotrophs act as consumers.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life 4

Two examples of Protista
Two examples of Protista are Amoeba proteus and Euglena viridis.

Question 5.
Mention three Identifying features of kingdom Fungi. Give two examples of Fungi.
Answer:
Identifying features of kingdom Fungi
Three identifying features of kingdom Fungi are as follows-

1. Cell and celiular organisation: These are unicellular or multicellular eukaryotic organisms. Cell wall typically contains chitin. Glycogen is the distinctive stored food. Multicellular forms often develop hyphae or mycelium.

2. Mode of nutrition: These are mostly saprophytic. They collect nutrition from dead and decaying organic matters. Some are parasitic, which draw nutrition from living plants and animals. Few symbiotic forms obtain nutrition with the help of their photosynthetic partners.

3. Role in ecosystem: All saprophytic forms act as decomposers. Parasitic forms play the role of consumers.
WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life 5
Two examples of Fungi
Two examples of Fungi are Agaricus bisporus and Penicillium notatum.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Question 6.
Mention three identifying features of kingdom Plantae. Give two examples of Plantae.
Answer:
Identifying features of kingdom Plantae
Three identifying features of kingdom Plantae are as follows-

1. Cell and cellular organisation: These are multicellular, organisms. The cells contain membrane-bound organelles and nucleus is well-organised (i.e. eukaryotic). Cell wall is typically rich in cellulose and other polysaccharides. Plastids and large vacuole present in cells. Tissue and tissue systems develop in the body.

2. Mode of nutrition: All members are autotrophs, which perform nutrition by the process of photosynthesis.

3. Role in ecosystem: All members act as producers of the ecosystem.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life 6
Two examples of Plantae
Two examples of Plantae are sunflower (Helianthus annus) and Riccia glauca.

Question 7.
Mention three identifying features of kingdom Animalia. Give two examples of Animalia.
Answer:
Identifying features of kingdom Animalia
Three identifying features of kingdom Animalia are as follows-

1. Cell and cellular organisation: These are multicellular, eukaryotic organisms. Cells have centrioles. Cell wall and plastids are absent. Body with definite shape and size. Body has well organised tissues, tissue systems, organs and organ systems.

2. Mode of nutrition: All members are heterotrophs, which perform holozoic mode of nutrition.

3. Role in ecosystem: All members act as consumers of the ecosystem.
WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life 7

Two examples of Animalia
Two examples of Animalia are starfish (Asterias rubens) and pigeon (Columba livia).

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life

Question 8.
Mention the advantages of five kingdom classification. According to five kingdom classification of the living world, which type of organisms are placed under kingdom Animalia?
Answer:
Advantages of five kingdom classification
The advantages of five kingdom classification are as follows-

  • All unicellular prokaryotes are separated from eukaryotic unicellular protists and placed under kingdom Monera. So this classification is justified.
  • Isolation of non-photosynthetic fungi from photosynthetic green plants is also justified because the mode of nutrition of fungi is different from that of green plants.
  • Separating Protozoa from Animalia, makes the classification system more accurate.
  • This classification rightly emphasises on the phylogeny of the living world.

WBBSE Class 9 Life Science Solutions Chapter 1.3B Five Kingdoms of Life 8
Organisms under kingdom Animalia:
According to five kingdom classification of the living world, all heterotrophic, multicellular organisms, having cells without cell wall and holozoic mode of nutrition, are included under kingdom Animalia. It comprises all the consumers of different ecosystem.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy offer valuable context and analysis.

WBBSE Class 9 Science Chapter 1.3A Question Answer – Classification of Diversity of Life: Taxonomy

Very Short Questions and Answers : (1 mark for each question)

Question 1.
Who introduced the concept of species?
Answer:
The concept of species was introduced by John Ray.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Question 2.
Name the scientist who gave the modern definition of species.
Answer:
Scientist Ernst Mayr (1966) gave the modern definition of species.

Question 3.
Name the systematic framework of classification with fixed number of rank.
Answer:
The systematic framework of classification with fixed number of ranks, is called hierarchy.

Question 4.
What is the scientific name of India’s national fruit?
Answer:
The scientific name of India’s national fruit (mango) is Mangifera indica.

Question 5.
What is the full form of ICZN?
Answer:
Full form of ICZN is International Code of Zoological Nomenclature.

Question 6.
Before which year, the published scientific names of animals were considered invalid?
Answer:
Before the year 1758 , the published scientific names of animals were considered invalid.

Question 7.
Name an aquatic animal having same common name and generic name.
Answer:
Octopus is an aquatic animal, having same common and generic name.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Question 8.
Give an example of a fish having same generic and specific name.
Answer:
Scientific name of catla fish (Catla catla) has same generic and specific name.

Question 9.
Name the branch of biology that deals with identification, classification and nomenclature of organisms.
Answer:
The branch of biology that deals with identification, classification and nomenclature of organisms, is known as taxonomy.

Question 10.
In which edition of ‘Systema Naturae’ was the binomial nomenclature of animals accepted by ICZN?
Answer:
In the 10th edition of ‘Systema Naturae’, the binomial nomenclature of animals was accepted by ICZN.

Question 11.
Which year’s edition of ‘Species Plantarum’ was accepted by ICBN for binomial nomenclature of plants?
Answer:
The edition of ‘Species Plantarum’ published in the year 1753, was accepted by ICBN for binomial nomenclature of plants.

Question 12.
Define characterisation.
Answer:
Characterisation is an important feature of taxonomy which involves the process of listing the identifying features of collected specimen.

Question 13.
Name a terrestrial animal, having same common and scientific name.
Answer:
Gorilla is a terrestrial animal, which has same common name and scientific name (Gorilla gorilla).

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Question 14
Which type of organisms are mostly known by their scientific names?
Answer:
Most of the protozoa are known by their scientific names, such as Amoeba, Paramoecium etc.

Short Questions and Answers : (2 marks for each question)

Question 1.
How did the word ‘taxonomy’ originate?
Answer:
The word ‘taxonomy’ originated from two Greek words-‘taxis’ meaning ‘rank’ and ‘nomos’, meaning ‘law’ or ‘custom’. Therefore, the word ‘taxonomy’ literally means the ‘custom of ranking.’

Question 2.
What are the three basic features of Linnaean taxonomy?
Answer:
Three basic features of Linnaean taxonomy are-

  • Characterisation of living organisms based on certain observable features
  • Naming the organisms according to binomial nomenclature and
  • Placing the individuals into seven major levels of hierarchical ranks.

Question 3.
Mention the elements of discussion under taxonomy.
Answer:
The main elements of discussion under taxonomy are-

  • identification
  • nomenclature
  • classification and
  • documentation.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Question 4.
What is meant by identification?
Answer:
Identification is a taxonomic process of separating out any organism from a cluster of other forms, on the basis of its distinctive features.

Question 5.
What does spot identification mean?
Answer:
Spot identification is the process of separating out any plant or animal instantly from a cluster of other forms, on the basis of some external features.

Question 6.
What is meant by categorisation or grouping?
Answer:
The taxonomic process by which any organism is placed under a taxon or rank, based on its similarities with the other members of that group, is called grouping or categorisation.

Question 7.
What is meant by nomenclature?
Answer:
Nomenclature is a taxonomic process of providing a scientific name to a properly identified plant or animal, according to the internationally accepted rules in order to distinguish it from others.

Question 8.
What is classification?
Answer:
Classification is a taxonomic process of placing or grouping organisms into proper taxonomic categories on the basis of similarities in characters.

Question 9.
What is meant by documentation?
Answer:
Documentation is the scientific method of preservation of the type specimens, their description and all relevant data in museum or in laboratories, after the completion of taxonomic processes like identification, nomenclature and classification of a specimen.
WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life Taxonomy 1

Question 10.
What are taxonomic categories?
Answer:
Taxonomic categories are the units in which plants or animals are grouped during classification. Species, genus, family, order, class, phylum etc. are the examples of different taxonomic categories.

Question 11.
What is taxon?
Answer:
Taxon is the basic unit of hierarchy, which is a rank, given to a group of organisms with similar features, during classification.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Question 12
What is systematics?
Answer:
According to Simpson (1961), systematics is the scientific study of the kinds and diversities of organisms and relationship among them. The terms, systematics and taxonomy, often complement each other.

Question 13.
Mention the main objective of systematics.
Answer:
The main objective of systematics is to assort different organisms on the basis of their similarities and dissimilarities, so as to determine the inter-relationship amongst them and to point out their origin and trend of evolution.

Question 14.
Mention two problems of using common name of organisms with example.
Answer:
Two problems of using common names are:

  • Common names vary with regional languages, due to which an organism cannot be recognised universally. For example, crow is called ‘kak’ in bengali, ‘kawa’ in hindi, ‘corneille’ in french, ‘karasu’ in japanese etc.
  • Common name may create identity crisis. For example, silver fish is an insect, but the name apparently indicates a fish.

Question 15.
What is Linnaean hierarchy?
Answer:
The five-category system of hierarchical classification system proposed by Linnaeus in the 10th edition of his famous book, ‘Systema Naturae,’ is known as Linnaean hierarchy. He classified the living organisms into five categories, which was later modified into seven categories.
WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life Taxonomy 2

Question 16.
What is binomial nomenclature?
Answer:
Binomial nomenclature is the method of providing a scientific name to an organism. The name should contain two distinct epithets, the first one being genus and the second one is species. For example, Panthera tigris is the binomial nomenclature of tiger.

Question 17.
What is trinomial nomenclature?
Answer:
Trinomial nomenclature is the method of providing a scientific name to an organism where the name should contain three distinct epithets, genus, species and sub-species. For example, Homo sapiens sapiens is the trinomial nomenclature of human.

Question 18.
Mention the seven categories of modified Linnaean hierarchy.
Answer:
Seven categories of modified Linnaean hierarchy, from highest to lowest rank are
Kingdom → Phylum → Class → Order → Family → Genus → Species.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Question 19.
What is meant by structure of hierarchy? Represent the structure of Linnaean hierarchy.
Answer:

  • Structure of hierarchy: The arrangement of all categories of hierarchy from the base to the top collectively forms the structure of hierarchy.
  • Structure of Linnaean hierarchy: The structure of Linnaean hierarchy can be respresented as follows-

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life Taxonomy 3

Question 20.
Mention the importance of classification.
Answer:
The importance of classification are as follows-

  • By means of classification, an organism can be sorted out easily and quickly from a cluster of organisms.
  • Classification helps to determine the inter-relationship amongst different groups of organisms.

Long Questions and Answers : (5 marks for each question)

Question 1.
Write down the brief history of the development of taxonomy in the pre-Linnaean period.
Answer:
Pre-Linnaean development of taxonomic science
Taxonomy is one of the oldest branches of biology, which has developed gradually since ancient time. The developmental phases of taxonomy, according to the ages, have been discussed below.
WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life Taxonomy 4
(1) Ancient age: The concept of taxonomy has developed in India about 2500 years back. The glimpse of classification was noticed in Rig veda, Manusamhita and Agnipuran. Manu, an ancient sage, classified plants into oshadhi, banaspati, briksha, gulma, trina and balli. In ‘Briksha ayurveda’, Rishi Parashar (1500 BC) classified plants on the basis of morphological features.

Susruta, the famous ancient Indian medic, classified medicinal plants into 37 genera. Greek philosopher, Aristotle (384-322 BC) classified animal kingdom in two divisionsAnaima (having colourless blood) and Enaima (having red blood). Theophrastus (371-287 BC), the disciple of Aristotle, described 480 species of plants and classified those into trees, shrubs and herbs, in his famous book, ‘The Historia Plantarum’

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

(2) Roman age: Famous Roman naturalist Pliny the Elder (23-79 AD), classified plants in his book, ‘Naturalis Historia’ on the basis of their medicinal qualities. Roman physician Discordies, described about 600 medicinal plants in his famous book ‘The Materia Medica.’

(3) Middle age: Italian botanist Caesalpino (1583), in his famous book ‘The Plantis’, classified 1500 plants into trees, shrubs and herbs. In his classification, he put emphasis on the character of fruits and seeds. For this great work, Caesalpino is regarded as the pioneer of plant taxonomy.

Gaspard Bauhin (1596) classified 6000 species of plants in his famous book ‘Pinax’. He was the first person who tried to show the difference between genus and species. Famous scientist John Ray (1627-1705), classified plants based on the basis of the number of cotyledon of seeds in his book ‘Methodum Plantarum’.

Question 2.
Write down the brief history of the development of taxonomy in pre-Linnaean period.
Answer:
Unnaeus’s role in developing modern taxonomy:

Modern taxonomy was set into light after the work of great Swedish scientist Carolus Linnaeus. He was the pioneer of scientific classification of plants and animals. In 1751, he first suggested the concept of binomial nomenclature in his famous book Philosophia Botanica

He studied numerous plants and animals, which he described in the latest edition of his two famous books, ‘Species Plantarum’ (1753) and ‘Systema Naturae’ (1758), respectively.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life Taxonomy 5

Taxonomists of post-Linnaean period:
Augustin de Candolle (1799), George Bentham (1862-1883), Joseph Dalton Hooker (1855), Adolph Engler, Karl Prantl (1887-1915), John Hutchinson (1926), Ernst Mayr (1963) are some of t

he renowned scientists who have enriched the taxonomic science to a great extent in the post-Linnaean period.

In last twenty years, there was immense development noticed in the field of systematic classification of plant kingdom based on phylogenetic analysis. Takhtajan (1997), Cronquist (1981) etc. played promising role in this aspect.

Question 3
What is meant by taxonomic hierarchy? How did Linnaean hierarchy modify in course of time?
Answer:
Taxonomic heirarchy
Taxonomic hierarchy is the sequential arrangement of various categories or units of classification comprising of different taxa, from larger to smaller ranks. This includes seven categories.

Modification of Linnaean hierarchy
In course of time, newer variants of organisms have been discovered. Modern taxonomists faced problems in positioning those variants in the prevailing seven-step format. Consequently, Simpson (1961) suggested a
21-step hierarchy for animal classification.

In this format, a new step ‘tribe’ was being inserted in between genus and sub-family. Besides this, some intermediate steps were also inserted in between the main steps prefixed with ‘supra,’ ‘sub’ and ‘infra’. Later, ICBN proposed a 24-step hierarchy structure.

Here, few more new steps were introduced, namely ‘section’ and ‘series’ between genus and species and ‘variety, ‘form’ and ‘clone’ after species. However, the intermediate steps, prefixed with ‘supra’ and ‘infra’ are discarded. Thus, the old Linnaean hierarchy is modernised in course of time.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Question 4.
Describe every category of taxonomic hierarchy with example.
Answer:
Categories of taxonomic hierarchy
Taxonomic hierarchy includes seven categories or ranks, which are described below.
1. Kingdom: It is the topmost category of taxonomic hierarchy. All different phyla or divisions constitute a kingdom. American scientist, R H Whittaker (1969) classified the whole living world into five different kingdoms-Monera, Protista, Fungi, Plantae and Animalia. Example-Human belongs to kingdom ‘Animalia’ and mango tree belongs to kingdom ‘Plantae.’

2 Phylum/Division: Related classes of animals constitute a phylum. In case of plants, this category is known as division. Example-In case of human, phylum is ‘Chordata’ and for mango tree, division is ‘Angiospermae.’

3 Class: A class consists of several related orders.
Example-Human belongs to class ‘Mammalia’ and mango tree belongs to class ‘Dicotyledoneae.’

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life Taxonomy 6

4. Order: Several related families add up to create an order. Example-Human belongs to the order ‘Primates’ and mango tree belongs to the order ‘Sapindales’.

5. Family: All related genus together comprise a family. Example-Family of human is ‘Hominidae’ and for mango tree, it is ‘Anacardiaceae’.

6 Genus: Several related species constitute a genus. Example-Genus of human and mango tree are Homo and Mangifera respectively.

7 Species: It is the lowest category of taxonomic hierarchy. The taxon under this category include the group of naturally interbreeding organisms, which remain reproductively isolated from other related groups.
Example-Species of human and mango tree are sapiens and indica respectively.

Question 5.
What are the advantages of hierarchical classification? Mention the systematic position of mango tree according to Linnaean hierarchy.
Answer:
Advantages of hierarchical classification
The advantages of hierarchical classification has been discussed below.
1. Inter-relation amongst groups: Hierarchical system of classification provides ready information necessary to determine inter-relationships amongst two groups of plants or two groups of animals.

2. Flawless grouping: Before this system of classification, characteristic features of the sample specimens were studied vividly. Emergence of this system of classification helps us to study the characteristics of the sample specimens more specifically. Therefore, the grouping becomes flawless.

3. Easy identification of taxon: From a hierarchical classification, any taxon can be easily identified.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

4. Other advantages: In this system of classification, repetition of characteristic features does not occur amongst the taxa of higher and lower categories. Only additional similarities are added to the lower categories.

Systematic position of mango tree
The systematic position of mango tree has been represented below.
WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life Taxonomy 7

Question 6.
Mention the rules of binomial nomenclature.
Answer:
Rules of binomial nomendature

The basic principles of binomial nomenclature was initially proposed by Linnaeus. Later in the 19th and 20th century, several international bodies of taxonomy, namely ICBN, ICZN, ICBacN, ICVN and ICNCPP reviewed the prevailing rules and published the final edited version of the rules of binomial nomenclature. The most important rules are as follows—

1. Every organism must have a definite scientific name in Latin or Greek, comprising of two epithets – a generic name and a specific name.

2. Each of the epithets must not be composed of less than three or more than twelve roman alphabets. The generic name is a noun, which should be written first, starting with a capital letter.

3. A generic name cannot be repeated in any other organism of the same or different kingdom.

4. Specific name should be written after generic name. It should be written in small letters.

5. A specific name may be repeated under different genus.

6. The name of the discoverer may be mentioned in full or in abbreviation, after the specific name.

7. A scientific name should be printed in italics. If handwritten, each epithet should be separately underlined. For example, scientific name of mango tree should be written as Mangifera indica L. (Here L. stands for Linnaeus, the discoverer).

8. Any plant name, used before publication of ‘Species Plantarum’ (1753) and animal name, used before publication of 10th edition of ‘Systema Naturae’ (1758) must be discarded.

9. If a single organism is assigned two different names by two separate discoverers in different times, the former will be accepted and the latter will be discarded. This is known as Law of priority.

10. Detailed description with photograph of the sample used for nomenclature, must be published in any internationally accepted science journal. The type specimen, used for the nomenclature, must be preserved in any museum competent for such job.

WBBSE Class 9 Life Science Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy

Question 7.
Mention the systematic position of human according to taxonomic hierarchy and the important characteristic features of different taxa.
Answer:
Systematic position of human and characteristic features of different taxa

MSBM Taxon Characteristic features
1. Kingdom Animalia Multicellular, cells without plastids and cell wall, heterotrophic, capable of locomotion
2. Phylum Chordata Notochord present at any stage of the life cycle, dorsal tubular nerve cord present, pharyngeal gill slits and post anal tail present
3. Class Mammalia Body covered with hair, sweat glands and sebaceous glands present in skin, mammary glands and external pinna present
4. Order Primata or Primates Palm and foot can grip any object, all digits have nails, vision is strong but sense of smell (olfactory sense) limited
5. Family Hominidae Body erect, capable of bipedal movement, hands shorter than legs
6. Genus Homo Brain is advanced and structurally complex, structure of palm is well developed (to use and prepare tools), capable of talking
7. Species sapiens High forehead, distinct lower jaw-line, culturally advanced

 

WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches

Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 1.2 Biology and its Branches offer valuable context and analysis.

WBBSE Class 9 Science Chapter 1.2 Question Answer – Biology and its Branches

Very Short Questions and Answers : (1 mark for each question)

Question 1.
What is anatomy?
Answer:
Anatomy is the study of the structure and location of internal organs and organ systems of animals and plants.

Question 2.
What is genetics?
Answer:
Genetics is the study of genes and hereditary features of organisms.

WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches

Question 3.
What is embryology?
Answer:
Embryology is the study of structure and development of embryos of living organisms.

Question 4.
What is evolutionary biology?
Answer:
Evolutionary biology is the study of origin of life and trends of changes in different forms of life with time.

Question 5.
What is biogeography?
Answer:
Biogeography is the study of distribution of plants and animals in different geographical regions.

Question 6.
What is cybernetics?
Answer:
Cybernetics is the science that deals with the technique of communications and control systems in both machines and living organisms.

Question 7.
What do you mean by hybridization?
Answer:
Hybridization is the process of crossing two genetically different individuals to produce an offspring with a different, often preferred, set of characters.

WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches

Question 8.
Mention any three branches of applied biology.
Answer:
Three branches of applied biology are — sericulture, apiculture and animal husbandry.

Question 9.
What is agriculture?
Answer:
Agriculture is the scientific practice of cultivation of commercially important crops.

Question 10.
What is horticulture?
Answer:
Horticulture is the scientific practice of production of flowers and fruits.

Question 11.
What is apiculture?
Answer:
Apiculture is the scientific practice of rearing honeybees in artificial hives and extracting honey from it.

Question 12.
What is sericulture?
Answer:
Sericulture is the scientific practice of rearing silkworms and extracting silk fibres from cocoons for economic purpose.

Question 13.
What is animal husbandry?
Answer:
Animal husbandry is the practice of breeding and rearing domestic animals like cattles, pigs, poultry birds etc. for production of milk, meat and eggs.

Question 14.
What is pharmacy?
Answer:
Pharmacy is the study of principles and practices of developing drug for therapeutic use in man, animals and plants.

WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches

Question 15.
What is silviculture?
Answer:
Silviculture is the study of principles and practices of cultivation of trees for wood and use of timber and its by-products.

Question 16.
What is entomology?
Answer:
Entomology is the study of different insects which are useful and harmful to man, animals and plants.

Short Questions and Answers : (2 marks for each question)

Question 1.
What is biology?
Answer:
The branch of science that deals with the study, investigations, experiments, observations and discussions on the origin, development, structural features and physiological activities of different living organisms, is known as biology

Question 2.
What do you mean by applied branches of biology?
Answer:
Applied branches of biology are those branches of biological science, in which, knowledge obtained from biology is applied for the welfare of human, animals and plants.

Question 3
What is zoology?
Answer:
The branch of biological science that deals with the study of morphology, anatomy, physiology, taxonomy, geographical distribution and conservation of animals, is known as zoology.

Question 4.
What is botany?
Answer:
The branch of biological science that deals with the study of morphology, anatomy, physiology, taxonomy, geographical distribution and medinical uses and conservation of plants, is known as botany.

Question 5.
What is physiology?
Answer:
The branch of biology that deals with the study of different activities and reactions related to various metabolic functions of living organisms, is called physiology.

Question 6.
What is taxonomy?
Answer:
Taxonomy is the oldest branch of biology, that deals with the identification, nomenclature and classification of living organisms on the basis of certain principles and processes.

Question 7.
What is microbiology?
Answer:
Microbiology is a branch of biological science, that deals with the study of microorganisms like virus, bacteria and all other microscopic organisms which are useful and harmful to human, animals and plants.
WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches 1

Question 8.
What is biochemistry?
Answer:
Biochemistry is a branch of science, developed by the combination of biology and chemistry. in order to study the nature of various chemicals, their classification and reaction processes occurring in the living organisms.

Question 9.
What is biophysics?
Answer:
Biophysics is an interdisciplinary branch of science, that is developed by (he combination of biology and physics. Ir deals with the study and explaination of the critical structure of various organs and the physical activities related to movement and locomotion, food capturing etc. of living bodies under the light of physics. Various instruments have been invented with the help of biophysics, such as endoscope, ultrasonograph, microscope etc.
WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches 2

Question 10.
What is molecular biology?
Answer:
The branch of biology that deals with the study of molecular structures of different intracellular biomolecules, their functions and applications, is known as molecular biology.

Question 11.
What is statistics?
Answer:
The branch of science, that deals with the collection, analysis and interpretation of data and finally presentation and organisation of the collected data, is known as statistics.

Question 12.
What is immunology?
Answer:
Immunology is a branch of science, that deals with the study of structure and function of body’s immune system and the nature of reactions occuring within the body between different antigens and antibodies.

Question 13.
What is astrobiology or exobiology?
Answer:
Astrobiology or exobiology is a combination of biology and space science, which is concerned with the study of the effect of hostile environment of outer space on various life activities of organisms on earth and different biochemical reactions.

Question 14.
What are the objectives of studying exobiology?
Answer:
The most important objective of studying exobiology is to find those organisms, that can withstand extreme conditions in space. Study of these organisms gives us an idea of those life forms, which came into being in extremely hostile environment of primitive earth. Study of this subject also gives us an idea of the reactions, which took place during abiogenesis of life on earth.

Question 15
Mention the different branches of cinical biology.
Answer:
The different branches of clinical biology are-immunology, serology, haematology, oncology, radiation biology, IVF (In vitro Fertilisation) technology, veterinary science etc.

Question 16
What is serology?
Answer:
Serology is the scientific study or diagnostic examination of blood and serum, especially with respect to the response of the immune system to pathogens or introduced substances.

Question 17
What is meant by pearl culture? What is lac culture?
Answer:

  • Pearl culture: Pearl culture is a branch of applied biology that deals with the methods and techniques of rearing pearl oysters and extraction of pearl from them.
  • Lac culture: Lac culture is a branch of applied biology that deals with the methods of rearing lac insects and extraction of shellac (a resin secreted by the female lac bug) from them.

Question 18.
What is meant by bioenergetics? What is thanatology?
Answer:

  • Bioenergetics: The branch of biology that deals with the transformation of energy required for the synthesis and breaking up of biomolecules, is known as bioenergetics.
  • Thanatology: Thanatology is the branch of science, that is concerned with the study of changes in a body after death and finding the cause of death.

Question 19.
What is bionics?
Answer:
Bionics is a new branch of science developed by the combination of biology and electronics to study the mechanical systems that function like living organisms or part of living organisms.

Question 20.
What is gerontology?
Answer:
Gerontology is a branch of science, that deals with ageing process. It is also known as geriatric studies. It mainly deals with the physical activities and problems faced during old age, senescence process of living cells, developing anti-oxidant medications etc.

Question 21.
What is biotechnology?
Answer:
Biotechnology is a broad discipline of bioscience, which involves the exploitation of biological processes for industrial and other purposes, especially the genetic manipulation of microorganisms for the production of antibiotics, hormones, etc.

Question 22.
Write two objectives of studying biology.
Answer:
Two objectives of studying biology are:

  • To understand the relationship of living organisms with primary components of the environment and their interdependence.
  • To gain knowledge about our local flora and fauna and developing healthy interaction with them.

Long Questions and Answers : (5 marks for each question)

Question 1.
Give a brief idea wa different brauches of classical biology.
Answer:
Branches of classical biology
Different branches of classical biology are discussed below.

  • Morphology: This Is the branch of classical biology, that deals with the study of morphs I.e. size.
    shape and external features of living organisms.
  • Cytology: This branch of biology deals with the study of structure and function of cells.
  • Histology: The study of structure, distribution and function of tissues of living organisms, is called histology.
  • Anaty: [his branch of biology deals with the structures of different Internal organs of plants and animals.
  • Pyslolog: This is the branch of classical biology, that involves the study of various metabolic reactions and the functional activities of life.
  • Genetics: This branch of biology deals with the study of heredity and variations of inherited features.
  • Evolutionary biolo: This is the study of origin of life and gradual complexities of organisms.
  • Ethology: This branch of biology is concerned with the study of behaviour of organisms.
  • Ecology: This branch of classical biology deals with the study of interrelation between organisms and the environment.
  • Taxonomy: This is the oldest branch of classical biology that deals with the theoritical study of classification of living organisms including its basic principles and processes. It involves identification, nomenclature and classification of organisms.
  • Immunology: This branch of science deals with the study of immune system of our body and the reactions of antigens and antibodies occuring in our body.
  • Embryology: This branch of science deals with the structure and development of embryo of living organisms.
  • Pathology: This branch of science deals with the study of different diseases, their causes and preventive measures.
  • Paleontology: This branch of classical biology deals with the study of extinct organisms, through their fossils and, thus, knowing their geological history.

Question 2.
Give a brief idea on different branches of applied biology.
Answer:
Branches of applied biology
Different branches of applied biology are discussed below.
1. Agriculture: This branch of applied biology deals with the practice of cultivation of crops and vegetables.

2. Horticulture: This is a branch of applied biology, which deals with the scientific practice of cultivation of flowers and fruits.

3. Forestry: This branch of applied biology deals with the methods, which help to reduce deforestation, such as afforestation and conservation of forest.

4. Pharmacognosy: This branch of science deals with the rearing and conservation of medicinal herbs and study of crude drugs and herbal medicines.
WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches 3
5. Sericulture: This branch of science deals with the scientific practice of rearing silkworm and extracting silk fibres from cocoons, for economic interest.

6. Pisciculture: This branch of applied biology deals with the scientific practice of breeding, rearing and capturing fishes for economic purpose.

7. Apiculture: This branch of science deals with the scientific practice of rearing honeybees in artificial hives and extracting honey from them.

WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches 4

8. Pearl Culture: This is a branch of applied biology, that deals with the methods of rearing pearl oysters and extraction of pearl from them.

9. Lac culture: This branch of applied biology deals with the methods of rearing lac insects and extraction of shellac from them.

10. Poultry farming: This branch of applied biology deals with the breeding and rearing of poultry birds, for the production of eggs and meat.

11. Dairy farming: This branch of applied biology deals with the rearing of cattle for the production of milk.

12. Animal husbandly : This branch of applied biology deals with the practice of breeding of farm animals (cattle, pigs, horses etc.) in order to develop their genetic qualities for human profit.

13. Plant breedhg This branch of applied biology deals with various methods for production of improved variety of plants.

14. Molecular biology : The branch of science that deals with the study of different biomolecules and their activities within our body, is known as molecular biology.

15. Biochemistry : This branch of science deals with the study of chemical processes occurring inside living organisms.

16. Microbiology: It is the study of microorganisms that are useful or harmful to man, plants and animals.

Question 3.
Mention the relationship of biology with other branches of science.
Answer:
Relationship of biology with other branches of science:
In course of time, biological science has developed further by sharing its concepts with other fields of science. This gave rise to some new and modern branches of science subjects. Some of these are discussed below.

1. Biophysics: This branch of science has been developed by the combination of biology and physics. It deals with the study and explanation of the critical structures of various organs and physical activities related to movement, locomotion, food capturing etc. of living bodies, under the light of physics.

2. Biochemistry: This is a branch of science, developed by the combination of biology and chemistry. It deals with the study of nature of various chemicals, their classification and reaction processes occurring in the living organisms.

3. Biotechnology: This is a modern branch of science, developed for producing improved variety of plants or animals for human benefit, by means of genetic manipulation.

4. Biometry: This is a branch of science, developed by combination of biology, mathematics and statistics. This subject helps to analyse different events and facts of biology, under the light of statistics.

5. Bionics: This branch of science has developed by the combination of biology’ and electronics. This is the study of mechanical systems which function like living organisms or parts of living organisms.

6. Biogeography: This branch of science has developed by the combination of biology and geography. It deals with the study of the distribution of flora and fauna in different geographical regions.

7. Anthropology: This branch of science has been developed for the study of humankind, under the light of geography, sociology and palaeontology.

8. Palaeontology: This branch of science is developed by the combination of biology and geology. It deals with the study of the fossils of primitive life forms.

9. Bioinformatics: This branch of science has been developed by the combination of biology and computer science. It deals with the analysis of complex biological data, especially genetic codes.

10. Astrobiology or exobiology: This is a modern branch of science, developed by the combination of biology and space science to study the effect of environment of outer space on living organism of earth.

Question 4.
Explain the applications of biology in various fields.
Answer:
Applications of biology:
Some important applications of biology are discussed below.

1. Development in agriculture: The ever-growing population of our country led to the problem of food scarcity, thereby increasing the demand for food. Application of biology has solved this problem to a great extent. Biology is applied at its best in the field of agriculture, to increase the productivity and quality of crops. Various fields of application of biology in agriculture are —

  • Production of high-yielding varieties of crops: By using the knowledge of genetics and applying the techniques of hybridization, high-yielding varieties of paddy, wheat, maize and several other crops have been successfully produced.
  • Production of seedless fruits: Concept of genetics and horticulture are combined to produce seedless varieties of fruits and to improve the productivity and size of fruits.
  • Pest control: Concept of biotechnology has been applied to develop certain pest resistant varieties of crops and vegetables. Several pests are now controlled biologically by using predators and parasites.
  • Storing of crops and food: Inventions in the field of biology help us to protect and preserve crops and food for a longer period of time. ‘

2. Fish production: Knowledge of biology has been applied in induced breeding technique and composite fish culture, to increase fish production and to meet the growing demand.

3. Poultry and dairy: Knowledge of biology has been used for the advancement of poultry and dairy farming techniques. By this process, the production of eggs, meat and milk has been increased.

4. Preparation of medicines: Herbal medicines are used since ancient times. Study of biology has revealed several medicinally important plants and animal products, which are used for the benefit of human and animals. Knowledge of microbiology has helped to produce a number of antibiotics, such as penicillin, streptomycin, neomycin, tetracycline etc.
WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches 5
5. Application of biology in space: Chlorella is the most photosynthetically efficient green alga. It is cultured in space stations, to maintain a continuous supply of oxygen and removal of carbon dioxide. Many microbes and other organisms are studied in space laboratories to know the effect of extreme conditions of space on life forms.

6. Industrial production: Industries like sericulture, lac culture, pearl culture are different wings of biology. The concepts of biology are utilised to increase the production of cosmetics, medicines, textile, paper, plastic, rubber, leather, wood, tea, coffee, bakery and brewery industries.

7. Controlling environmental pollution: Biological notions help us to control environmental pollution. Afforestation, social forestry and conservation of forest are some of the positive steps, undertaken globally for pollution control.

WBBSE Class 9 Life Science Solutions Chapter 1.2 Biology and its Branches 6

8. Population control: Population explosion is the burning problem of present world. By applying different concepts of biology and medicine, scientists have invented different modern and effective birth contol techniques for controlling population.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 1.1 Basic Properties of Life offer valuable context and analysis.

WBBSE Class 9 Science Chapter 1.1 Question Answer – Basic Properties of Life

Very Short Questions and Answers : (1 mark for each question)

Question 1
Mention five common signs of life.
Answer:
Reproduction, growth, metabolism, response to stimuli and adaptability are the five common signs of life.

Question 2.
What does reproduction mean?
Answer:
Reproduction is the biological process by which new individuals or offsprings are produced from their parents.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 3.
Define excitability.
Answer:
Excitability is defined as a response of a living organism to any external and internal stimulus.

Question 4.
What is meant by response?
Answer:
The reaction shown by a living organism towards any impulse, is called response.

Question 5.
What does metabolism mean?
Answer:
A set of complex physiological and chemical processes necessary for sustaining life, involving formation and breakdown of various nutrients within the body is called metabolism.

Question 6.
What is growth?
Answer:
Growth is the irreversible increase in dry mass and size of a living body.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 7.
What is meant by biopoiesis?
Answer:
Biopoiesis is the concept of the origin of living organisms from non-living matters.

Question 8.
Who first suggested that living organisms originated from non-living matters?
Answer:
Philosopher Aristotle first suggested that living organisms originated from non-living matters.

Question 9.
From where did primary organic micromolecules originate from inorganic compounds?
Answer:
Primary organic micromolecules originated in the primitive atmosphere from simple inorganic compounds.

Question 10.
How was the atmosphere on earth before the origin of life?
Answer:
Before the origin of life, earth’s atmosphere was reducing in nature.

Question 11.
Why the atmosphere of primitive earth was reducing in nature?
Answer:
The atmosphere of primitive earth was reducing in nature because there was no free oxygen in the atmosphere.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 12.
Name the two scientists who suggested that organic micromolecules originated on earth by chemical reactions amongst simple inorganic compounds.
Answer:
Scientists Alexander Oparin and JBS Haldane, first suggested that organic micromolecules originated on earth by chemical reactions amongst simple inorganic compounds.

Question 13.
How did primary organic micromolecules reach the earth’s surface?
Answer:
Primary organic micromolecules reached the earth’s surface through rainwater.

Question 14.
Who coined the term ‘primordial soup’?
Answer:
Scientist A1 Oparin coined the term ‘primordial soup’ to denote the primitive oceanic water rich in organic matter.

Question 15.
Which term was used by Haldane to indicate the boiling hot oceanic water of the primitive earth rich in organic matter?
Answer:
Haldane denoted the organic matter-rich boiling hot oceanic water of the primitive earth as ‘hot dilute soup’.

Question 16.
What are proteinoids?
Answer:
Proteinoids are tiny clusters of protein molecules formed abiotically from amino acids by cross-linkage.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 17.
What are microspheres?
Answer:
Microspheres are spherical clusters of proteinoids, covered with thin film of phospholipids.

Question 18.
Name two primitive forms, which are considered as predecessors of living organisms on earth.
Answer:
Microspheres and coacervates are two primitive forms, which are considered as predecessors of living organisms on earth.

Question 19.
Which organic matters constitute a protobiont?
Answer:
A protobiont is constituted of organic matters like nucleic acids, lipids and various protein molecules.

Question 20.
What is meant by alpha (α) diversity?
Answer:
Alpha (α) diversity indicates the richness of species in a specific area or an ecosystem.

Question 21.
What is meant by beta (β) diversity?
Answer:
Beta (β) diversity is the measure of the comparative turnover of species in two different habitats of an ecosystem.

Question 22.
What is meant by gamma (γ) diversity?
Answer:
Gamma (γ) diversity is the overall biodiversity of a large geographical realm, consisting of many typical habitats and ecosystems.

Question 23.
What are the two main causes of biodiversity on earth?
Answer:
Genetic variation and natural selection are the two main causes of biodiversity on earth.

Question 24.
Which class of animals shows the highest level of diversity in India?
Answer:
In India, birds show the highest level of diversity, where about 12.6% of global bird species are found.

Question 25.
What is meant by biodiversity hotspot?
Answer:
Biodiversity hotspot is a geographical area that provides shelter to a very rich variety of endemic species that are facing the threat of extinction.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 26.
How many biodiversity hotspots are there in India?
Answer:
In India there are three biodiversity hotspots-the Western Ghats, the Himalayas and the Indo-Burma regions.

Question 27.
How many biodiversity hotspots are there in the World?
Answer:
According to Conservation International (2004), there are 34 hotspots in the world.

Question 28.
Which type of diversity is also known as turnover diversity?
Answer:
Beta diversity is also known as turnover diversity.

Short Questions and Answers : (2 marks for each question)

Question 1.
What is life?
Answer:
Life is the condition that establishes the existence of a living organism on the basis of various characteristics such as growth, reproduction, metabolic activities, response to stimuli, adaptability, ageing, death etc.

Question 2.
What are non-living objects?
Answer:
Those objects which do not show any of the signs of life, such as growth, reproduction, metabolic activities, response to stimuli, ageing and senescence etc., are called non-living objects.
WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life 1

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 3.
What is meant by life cycle?
Answer:
The cyclic course of events undergone by an organism, starting from its birth followed by growth, maturity, reproduction, ageing and finally death, is known as its life cycle.
WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life 2

Question 4.
Define heredity.
Answer:
Heredity is the process of transfer of different characteristics from parents to their offsprings.

Question 5.
What is evolution?
Answer:
Evolution is the slow, steady and continuous emergence of advanced and complex forms of life from primitive and simpler forms. It also involves change in heritable characters of biological population from one generation to the next.

Question 6.
What is meant by mutation? What is mutability?
Answer:

  • Mutation: Mutation is a sudden, permanent and inheritable transformation in living organisms, caused due to any change in chromosome or gene either naturally or by any external factor.
  • Mutability: The capacity of a living organism to undergo mutation is called mutability.

Question 7.
What is meant by variation?
Answer:
The dissimilarities in external or internal features or behaviours found amongst the different members of a species in a population, is called variation.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 8.
Give an example of response to stimuli shown by plant.
Answer:
The leaves of ‘touch me not’ (Mimosa pudica) plant droop when touched. This is an example of response to stimuli shown by a plant.
WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life 3

Question 9.
What is meant by senescence?
Answer:
Senescence is the process of gradual and irreversible deterioration in the structural components of the body and decrease in the ability of a matured organism to deal with the stress of the environment.

Question 10.
what is meant by ageing? What is death?
Answer:

  • Ageing: Ageing is the process of growing older with time, that is genetically determined and environmentally modulated.
  • Death: Death is the ultimate disappearance of all signs of life from a living organism.

Question 11.
What does the ‘Ghemogeny of life’ mean?
Answer:
Chemogeny or chemosynthesis of life is the most modern concept, used to explain the biochemical origin of life on the earth. According to this concept, life originated naturally and spontaneously from simpler inorganic matters on earth, through various physical and chemical processes.

Question 12.
What is meant by ‘hoi dilute soup’?
Answer:
According to the theory of chemosynthesis, several organic molecules accumulated in the hot boiling water of the primitive ocean before the origin of life. Haldane denoted this hot broth of organic matter as ‘hot dilute soup!

Question 13.
What are coacervates?
Answer:
Coacervates are minute (1-100μ in diameter), spherical, bubble-shaped, colloidal matters, composed of a thin layer of organic molecules rich in lipids. Oparin (1924) first suggested this structure and named it coacervate.
WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life 4

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 14.
Mention the living features of microspheres.
Answer:
The living features of microspheres are as follows —

  • They are surrounded by a double-layered membrane
  • They show osmotic activity.
  • Certain protein molecules present in the microspheres, have enzymatic activity
  • Microspheres may divide through a process similar to binary fission.

Question 15.
What are proiocells?
Answer:
In the primitive sea, nucleic acid molecules entered into protein coacervates to take the shape of primitive cells. These primitive structures are known as protocells, in which the first sign of life was noticed.

Question 16.
What are naked genes?
Answer:
According to the chemosynthetic theory, during the last phase of ceil formation, purines, pyrimidines and pentose sugars united to form nucleic acids. These nucleic acid molecules were capable of seif-replication. They were devoid of histone and other proteins and as they were not surrounded by nuclear membrane. They were called naked genes.

Question 17.
What is meant by biodiversity?
Answer:
Biodiversity refers to the variety of different types of living organisms on the basis of structure, shape and behaviour found on earth, that are inhabiting different habitats of various ecosystems.

Question 18.
What is meant by genetic diversity?
Answer:
The different types of variations and combinations in the genetic composition among the individuals of a species is considered as genetic diversity. Due to genetic diversity, different individuals of same species look and behave differently.

Question 19.
What is meant by species diversity?
Answer:
The diversity in number, richness and evenness in distribution of various species in a biotic community is regarded as species diversity. This is estimaed by determining the number of variety of a species and the number of species Inhabiting a specified area.

Question 20.
What is meant by ecological diversity?
Answer:
The variation of several ecosystems in a large geograpical area or throughout the planet. is known as ecological diversity. The diversity of organisms from a microhabitat to a huge hiome is included under ecological diversity.

Question 21.
What is meant by species?
Answer:
Species is a group of closeI related individuals, which are capable of naturally interbreeding to produce fertile offsprings. They remain reproductively isolated from other groups.

Question 22.
How do variation occur In a population?
Answer:
Almost every individual of any sexually reproducing population is slightly different from one another. There are three main reasons behind —

  • Formatilin of different types of ganletes I due to crossing over,
  • Random union of gametes and
  • Change in the genetic material.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 23.
Give a brief note on the biodiversity of India.
Answer:
The biological diversity of India includes a huge variety of plant and animal species, their genetic variability and the organisation of species into different ecosystems. India is one of the seventeen megadiverse countries on earth. In global perspective, India houses about 7.6% of all mammals, 12.6% of all birds, 6.2% of all reptiles, 4.4% of all amphibians, 11.7% of all fishes and 6.0% of all flora.

Question 24.
What are the reasons for the loss of biodiversity?
Answer:
The main reasons for the loss of biodiversity are-

  • Deforestation,
  • Habitat fragmentation,
  • Environmental pollution,
  • Over exploitation of resources by Illegal hunting and poaching,
  • Natural calamities,
  • Alteration of natural environment due to green house effect, ozone layer depletion etc.,
  • Genetic incompatibility,
  • Introduction of exotic species etc.

Question 25.
What are the contributing factors of biodiversity?
Answer:
The contributing factors of biodiversity are-

  • Variation
  • Mutation
  • Speciation
  • Adaptation
  • Geographical isolation
  • Change in climatic condition
  • Change in habitat etc.

Question 26.
Compare between coacervate and microsphere.
Answer:

features Coacervate Microsphere
1. Definition These are minute spherical, bubble-shapped structures originating in the ‘hot dilute soup’ These are spherical clusters of proteinoids covered by a thin film of lipid bilayer
2. Function Plays an important role as the precursor of protocell Plays an Important role as the precursor of the early or primitive cell
3. Structural component Structure is composed of protein, fat, carbohydrate and nucleic acid Structure is composed mainly of proteins formed from proteinoids


Long Questions and Answers : (5 marks for each question)

Question 1.
Explain the basic properties of lite.
Answer:
Basic properties of life
From biological point of view, there are five basic properties of life. They are —

(1) Reproduction: Reproduction is a biological process by which living organisms give birth to offsprings in their lifetime, in order to protect their races from becoming extinct.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

(2) Growth: Growth is the irreversible increase in dry mass and size of a living body. A living organism must exhibit growth and development in due course of time.

(3) Metabolism: Metabolism is a set of life sustaining chemical reactions involving formation and breakdown of various nutrients within the body. Different metabolic activities like nutrition, respiration, excretion etc. take place in a living organism.

(4) Response to stimuli: Response to external and internal stimulus is an important character of a living organism. For example, if a moving millipede is touched, it coils around.

(5) Adaptability: Adaptability is a property of life where any living organism tries to adjust itself, either structurally or behaviourally, according to the changing environment.

Question 2.
Mention the differences between living beings and non-living objects.
Answer:
Differences between living beings and non-living objects

Features Living beings Non-living objects
1. Reproduction Living beings maintain their race by reproduction Non-living objects do not reproduce
2. Response to stimuli Living beings respond to external or internal stimuli Sensitivity to stimulus is absent in non-living objects
3. Growth Living beings grow gradually with time Non-living objects never show any growth
4. Metabolism Living beings perform various metabolic activities like photosynthesis, nutrition, respiration etc. Non-living objects never perform any metabolic function
5. Life span Ali living forms have a definite life span Non-living objects do not have any specific duration of existence
6. Movement and locomotion Living beings spontaneously exhibit movement and locomotion Movement occurs as a result of external influence
7. Protoplasm Cells of living organisms have active protoplasm Protoplasm is absent
8. Adaptability Living organisms can adapt themselves according to changing environment Non-living objects do not show any adaptation
9. Life cycle Living organisms have life cycle Non living objects do not have life cycle
10. Senescence and death Living organisms show signs of senescence and death Non-living objects do not show signs of senescence and death

Question 3.
Briefly describe the origin of earth and gradual changes in the primitive atmosphere according to the theory of chemosynthesis of life.
Answer:
Origin of earth and gradual changes in the primitive atmosphere
According to the theory of chemosynthesis of life or the theory of abiogenesis about 5-6 billion years ago, the earth originated from a huge explosion known as the Big Bang in the cosmos. At that time, the earth was a mass of burning gas. It took several million years to cool down and condense.

The temperature of primitive earth was around 5000°C — 6000°C. At that high temperature, it was difficult for certain gases such as hydrogen, nitrogen and oxygen etc. to exist independently in the atmosphere. As a result, they were present in the form of metallic or non-metallic compounds.

Therefore, the primitive atmosphere was reducing in nature due to the absence of free oxygen. With gradual decrease in temperature, water vapour condensed to form huge clouds, which came down on the earth in the form of rain. Gradually, the earth started to cool down further and condensed to form solid matters. The rainwater accumulated in the lowlands to form the primitive ocean.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 4.
Briefly describe chemogeny of life.
Answer:
Chemogeny of life
The process of synthesis of various organic compounds essential for the origin of life on the earth, was denoted as chemogeny by scientists Oparin and Haldane. This involves 3 steps. The steps of chemogeny are discussed below.

1. Origin of simple organic compounds: With gradual decrease in atmospheric tempertaure, the chemical components like hydrogen, methane, ammonia, water vapour etc., started reacting with each other to form simple organic molecules such as amino acids, simple sugars, fatty acids etc. The energy required to carry out these reactions was provided by lighting, ultraviolet ray and different cosmic rays. Through downpour, these compounds precipitated on earth and mixed in the primitive ocean.

2. Formation of complex organic compounds: The simple organic molecules condensed in the primitive ocean to form complex organic compounds such as proteins, carbohydrates, lipids, purines, pyrimidines etc. The boiling hot water of the primitive ocean containing the complex organic compounds was denoted as hot dilute soup by Haldane. Oparin termed the same as primordial soup.

3. Formation of coacervates: In the hot dilute soup, the organic matters, especially lipids, clustered to form a self-organised colloidal matter. Oparin named this bubble-shaped structures as coacervates. American scientist Sidney Fox (1957), denoted a similar substance as microsphere, which, according to him, was formed by unification of several globoid duster of proteins, called proteinoids, surrounded by a double-layered lipid membrane.

Question 5.
Explain biogeny or organic evolution of life.
Answer:
Biogeny or organic evolution of life:
According to Oparin, as the temperature of the atmosphere gradually started to cool down and simple organic compounds reacted with each other to form complex organic compounds by chemosynthesis, the boiling hot water of primitive ocean acted as the site of formation of lipid clusters, called coacervates. These coacervates absorbed nucleic acids and proteins from the primordial soup and transformed into a structure, capable of performing few metabolic activities which were named as protobionts.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

The protobionts were capable of synthesising some organic matters within it through various chemical reactions. Later, these protobionts transformed into self-replicating organic matters, which the scientists denoted as eubionts. These were the first living entity on earth. Later, cytoplasm formed within them and thus the earliest prokaryotic cells came into being.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life 5

Question 6.
Classify different levels of biodiversity.
Answer:
Levels of biodiversity : Biodiversity has been classified into three levels-

  • Genetic diversity,
  • Species diversity and
  • Ecological diversity,

1. Genetic diversity: The various types of variations and combinations in the genetic composition among the individuals of a species is considered as genetic diversity, Due to genetic diversity, individuals of same species look and behave differently. Example -The diversity in the genes of different varieties of paddy, wheat, dogs, etc.

2. Species divesity : The diversity in number, richness and evenness in distribution of various species in a biotic community is regarded us species diversity. This is estimated by determining the number of variety of a species and the number of species inhabiting a specified area. Example –The diversity of species inhabiting the mangrove forest of Sundarban.

3. Ecological diversity: The variation of several ecosystems in a large geographical area is known as ecological diversity. The diversity of organisms from a microhabitat to a huge biome is included under ecological diversity. American ecologist Whittaker (1965), classified ecological diversity into three different sub-types. They are—

  • α diversity: α diversity indicates the richness of species in a specific area or an ecosystem.
  • β diversity: β diversity is the measure of comparative turnover of species in two different habitats of an ecosystem.
  • γ diversity: γ diversity is the overall biodiversity of a large geographical realm, consisting of many typical habitats and ecosystems.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life

Question 7.
Describe the different types of variation along with their examples and significance.
Answer:
Types of variation
Variation is broadly classified into two types—

  • Continuous variation and
  • Discontinuous variation.

Continuous variation: Any characteristic of a species that changes gradually over a range of values is considered to exhibit continuous variation. It is represented by a line graph. Example — Variation in human height, skin colour and weight

Significance — Continuous ‘variation creates diversity amongst the members of same species. The characteristic features which undergo natural selection are ultimately transferred to the next generation.

Discontinuous variation: Any characteristic of a species having only a limited number of possible values is considered to exhibit discontinuous variation. It is represented by a bar graph. Example — Variation in human blood group and human eye colour.

Significance — Mutation is the prime reason behind discontinuous variation. Mutation leads to the development of new species at a comparatively faster rate. Discontinuous variation leads to species diversity.

WBBSE Class 9 Life Science Solutions Chapter 1.1 Basic Properties of Life 6
Question 8.
What are the important features of biodiversity?
Answer:
Important features of biodiversity
The important features of biodiversity are as follows –

  • Comparatively high level of biodiversity has been noticed in tropical and subtropical region than temperate region.
  • Rate of biodiversity is very high in tropical rain forests in terrestrial ecosystem and coral reefs in aquatic ecosystem.
  • Insects are the diverse of all living organisms (56.4% of total species).
  • Reduction of genetic diversity of a species gradually leads to its extinction.
  • Biodiversity is not evenly distributed in all parts of the world.

West Bengal Board Class 9 Life Science Book Solution in English WBBSE

WBBSE Class 9 Life Science Question Answer West Bengal Board

WBBSE Class 9 Life Science Book Solutions West Bengal Board in English Medium

WBBSE Class 9 Life Science Book Solutions West Bengal Board in Hindi Medium

WBBSE Class 9 Life Science Syllabus West Bengal Board 2024

Chapter 1 Life and its Diversity
Basic Properties of Life: How a living being is different from a non-living object?
Life shows some basic properties that are absent in non-living objects, e.g., the capacity to reproduce itself/new life, to uptake and use energy (metabolism), to respond to stimuli, etc. Explain in brief and in a simple way the basic properties of life with examples.

How does life come into being on Earth and when?
Chemical Origin of Life from Non-living Objects some 3.7 billion years ago; And then the evolution of the diversity of life forms from the earliest life form. A brief outline of the abiotic origin of life: pre-biotic conditions → precursor, biomolecules → coacervate/microsphere → protocells → earliest life forms.
Sources of Variations in Life: Heritable chance variations arise during the reproduction of living organisms and their adaptations to varying environments; Amount of diversity of the (biodiversity)-more than 30 million species and further variations within a species.

Biology is the Study of Patterns and Processes of Life and its Diversity: Why study Biology?
Biological studies at different levels and aspects. Different branches of Biology: what do they study (e.g. Biochemistry, Molecular biology, Immunology, Genetics, Histology, Anatomy, Physiology, Ecology, Behavioural Biology, Evolution, and other branches). Infusions of knowledge from other branches of science into Biology. Application of Physics, Chemistry, Mathematics, Statistics, Computers, and other branches; emergence of new branches of Biology. Applications of Modern Biology: Applications of Biology in agriculture, medicine, space science, and in other fields.

Classification of Diversity of Life: Taxonomy:
(a) Taxonomy and Taxonomic Hierarchy: Why taxonomy? What are the basic features of Linnaean taxonomy?
Development of modern taxonomy in Europe when naturalists started encountering a high diversity of new living organisms, especially from the tropics. A very brief history regarding the birth of modern taxonomy till Linnaeus. Hierarchical arrangement of classified groups. Explain the seven steps of taxonomic hierarchy schematically-(kingdom to species)-concerning one example from a plant (Mango) and one from an animal (Man). Binomial nomenclature: Explain briefly binomial nomenclature with an example.

(b) Five Kingdoms of Life: Five kingdoms of life: Name five kingdoms of life, mentioning three salient features of each kingdom-nature of cell and cellular organization, metabolic process, ecological role, and two common examples.

(c) Classification of Kingdom Plantae: How do different plants differ from each other?
Major groups (Algae, Bryophyta, Pteridophyta, Gymnosperm Angiosperm-Monocotyledon, and Dicotyledon). Comparing the distinguishing features of major groups with examples (tabular form).

(d) Classification of Kingdom Animalia: How different animals are similar and different from each other?
All major Phyla under Non-Chordata; Classification of Chordates upto class level. Three distinguishing features and two common examples of each group.

Chapter 2 Levels of Organization of Life
Biomolecules and their Behaviour: What are we made up of? Why these compounds are so important for our existence?
Elementary idea about the compounds of life-inorganic: water, acids, bases, salts, gases, etc. Organic: (i) Smaller molecules – simple sugars, amino acids, fatty acids, nucleotides (ii) Macromolecules-complex carbohydrates, protein, lipid, and nucleic acids. Different categories of biomolecules with examples (in a chart). Basic structural/compositional features of each type of biomolecule (detailed structure to be avoided). The major role of them in life processes (e.g. proteins act as structural materials, enzymes, etc. Role of ATP as the energy currency of a cell, etc.). Vitamins: Vitamin A, D, E, K, B-complex & C and their roles in the human body. Minerals: Mention the names of different minerals and their general role in the human body.

Cell: What are the organelles of a cell and how a cell is organized with such organelles?
Cell wall, cell membrane, cytoplasm, nucleus, mitochondria, plastid, endoplasmic reticulum, Golgi body, lysosome, vacuole, ribosome, centriole, microtubule. Elementary idea about the structures and functions of different organelles with the help of diagrams. Prokaryotic and eukaryotic cells; Plant and animal cells. Difference between Prokaryotic and eukaryotic cells with the help of diagrams; Difference between plant and animal cells with the help of diagrams.

Tissue: (i) Plant Tissue and its Distribution: What is a tissue? How plant tissues can be classified into different types?
Concept of tissue as an organization level within a multicellular living body. Tissues are organizations of similar or different types of cells performing particular functions in a multicellular living body. Meristematic tissue: Characteristic features, distribution, and functions (with diagrams), Permanent tissue: Characteristic features, distribution, types, and functions in tabular form (with diagrams)

(ii) Animal Tissue: What are the bases of differentiation/classification of animal tissues?
Tissue types: Describing different animal tissues (epithelial, connective, muscular, and nervous) – distribution, structure, and functions of each tissue (with the help of diagrams in tabular form)

Major Organs of the Human Body and their Function: What is an organ? How do different organs play a vital role in the human body?
Concept of an organ: Explaining an organ with examples – Skin, stomach, pancreas, lung, heart, spleen, kidney, brain, spinal cord, testes, and ovary – position and their routes. Elucidating the positions of different organs with the help of diagrams/ real pictures and two functions of each organ (with diagram in tabular form)

Chapter 3 Physiological Processes of Life
Plant Physiology: (i) Photosynthesis: What is the fate of entrapped solar energy in the plant body?
Concept of Photosynthesis: Photosynthesis is a process where light energy, normally from the sun, is converted into chemical energy (that can later be released to fuel the organism’s activities). This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water – The site of Photosynthesis. All chlorophyll-containing plant parts (examples) – Components of Photosynthesis and their role-CO2, H2O, sunlight and pigments chlorophyll and carotenoids. A brief outline of the roles of different components of photosynthesis; Explaining absorption and action spectra. Process: light-dependent phase and light-independent phase. A brief outline of major steps only Light-dependent phase: trapping of sunlight → activation of chlorophyll → photosynthesis of water → formation of end products of light-dependent phase (NADPH, O2, and ATP); Light-independent phase: Fixation of CO2 → formation of PGA → reduction of PGA → resynthesis of RuBP → synthesis of glucose (do not discuss the role of enzymes). Significance of Photosynthesis. Trapping and conversion of solar energy into food for plants and other organisms; O2 – CO2 balance.

(ii) Mineral Nutrition: How mineral nutrients are associated with the survival of plants?
Concepts of Macro-and Micro-nutrients with examples. Criteria for being qualified as macro-and micro-nutrients; Listing macro-and micro-nutrients; General functions of essential mineral nutrients; (e.g. formation of protoplasm, structure of enzyme, oxidation-reduction reaction, osmotic balance, formation of chlorophyll, buffer effect)

(iii) Transpiration: How do plants eliminate the excess water from their body?
Explanation: Elimination of excess water in the form of vapour; Comparing transpiration and evaporation – Sites of transpiration. Identifying the sites (stomata, lenticel, cuticular pore) – Factors controlling transpiration. Temperature, humidity, air movement, light, structure of leaf (leaf surface, cuticle, stomata) – Significance.  explain the significance (beneficial and harmful role).

(iv) Movement of Water, Food, and Gases: How different substances are transported in plant bodies?
Passive transport diffusion and osmosis – Features of diffusion and osmosis. Active transport – Elementary idea (lower to higher concentration, involvement of carrier molecule and requirement of energy) and examples – Cell to cell transport. Ascent of sap (role of root pressure and transpiration pull). Role of diffusion, osmosis, and active transport identifying the forces responsible for the movement of materials; Identifying, showing, and labeling the direction of flow of water; Recognizing the steps in the ascent of sap. Characteristic features of phloem transportation. Identifying showing and labeling the direction of the flow of food; Recognizing the steps in the translocation of food.

Respiration: (i) Organ level Respiration: Why Respiratory organs are so important?
Characteristic features of respiratory organs – Moist, extensive, and vascularized surface area – Respiratory sites of plants. Respiratory sites in plants – stomata, lenticels, pneumatophores – Respiratory organs of animals. Respiratory organs of animals – body surface, trachea(insect), gill(fish), lungs, and accessory respiratory organs (fish) – Lungs and breathing in humans. Inspiration, expiration, the role of the diaphragm and intercostal muscle; explaining with diagram the process of breathing (with the help of a working model of lungs) – Lungs and healthy life. Explaining in brief the role of breathing exercises and increased lung volume; cigarette smoking is harmful to the respiratory system.

(ii) Cellular Respiration: What is cellular respiration? In what way do different types of respiration differ from each other? How energy is utilized?
Concepts of cellular respiration. Oxidation of cellular substrate and production of energy; distinguishing respiration and combustion. Types of cellular respiration (Aerobic, Anaerobic, and Fermentation). Explain the occurrence, process of oxidation, and production of energy for each type of cellular respiration, the Steps of cellular respiration, and cellular sites where they occur. Mention the different steps of cellular respiration, i.e. Glycolysis → Krebs cycle → Terminal respiration. Signification of respiration, Mention cytoplasm and mitochondria as the sites. Liberation of energy and O2 – CO2 balance.

Nutrition: How do organisms process food inside their body?
Concepts of nutrition. Utilization of food for energy production, growth and repair, disease resistance – Types of nutrition. Plants: Explaining autotrophic and different types of heterotrophic nutrition (parasitic, symbiosis, saprophytic, and insectivory) with examples; Animals: parasitic, symbiotics, saprozoic, coprophagy, sanguinivory – Holozoic nutrition. Steps of holozoic nutrition and associated parts of the alimentary canal in humans. Alimentary system. Explaining the components of the dietary system and their role in nutrition; identifying, showing, and labeling parts of the alimentary system. Overview of digestion.

Mechanical and enzymatic digestion, hydrolysis – brief mention, hydrolysis, Digestive enzymes. Explaining the types with examples; site of secretion and their role in digestion (in tabular form); comparing and contrasting digestive enzymes. Absorption, Assimilation, and Egestion. Overview of absorption, assimilation, and egestion (site and process) – Metabolism. Explaining the fate of nutrients inside the cell; the brief idea of two types of metabolism with examples and mention significances, Dietary food intake, energy requirement, and associated problems. Concept of a balanced diet, BMR and its value; Calculation of energy required daily for an adult human; explaining metabolism-related problems in the human body.

Circulation: How different important substances are transported in the body of an organism? How is water utilized in the human body? Why blood is so important for human life?
Concept of circulation: Movement of nutrients, respiratory gases, metabolic wastes, synthesized substances, minerals, heat; Explaining components of the circulatory system of human blood, blood vessels, and heart, Types of circulation. Open and closed circulation with diagrams and examples of body fluids. Location and role of different body fluids-blood, lymph, sweat, urine, CSF, synovial fluid, tissue fluid, intracellular fluid, and Composition of blood (Plasma, Blood cell). Presenting composition of blood (with the help of chart); Plasma: Composition and functions; Blood cell (with the help of chart): origin, life span, and cellular characters of blood cells and their functions (in tabular form); Comparing and contrasting different blood cells with proper diagram, Blood group, and blood donation. Explaining the basis of grouping of blood (ABO & Rh factor); blood groups and significance (ABO incompatibility, Cross matching, Haemolysis). Misconception about blood donation. Coagulation of blood – Explaining coagulation of blood; factors involved (fibrinogen, prothrombin, tissue thromboplastin, calcium ion); major steps of the process and significance, Internal structure of human heart – Explaining chambers, valves, associated blood vessels, heart wall junctional tissues with the help of diagram or real pictures – Course of circulation of blood through heart – Explaining course of blood circulation through different chambers of heart; elementary idea of double circulation with diagram.

Excretion: How are metabolic wastes eliminated?
Concept of excretion: Explaining excretion (catabolism and production of harmful substances, their transport and elimination); outlining the water balance story of the human body and significance of excretion. Process of excretion in plants – Explain briefly the features of excretion in plants and processes (shedding of bark, leaves, and fruits with examples), Excretory products of plants. Nitrogenous and non-nitrogenous excretory products (tabular form) are excretory organs in animals. Contractile vacuole, flame cell, nephridia, malpighian tubule, kidney.

Excretory system of humans: Explaining, identifying, labeling, and analyzing the different parts of the excretory system of humans with the help of a diagram and their function – Nephron. Explaining and identifying structural components of nephron with the help of a diagram and their function; the role of the nephron in the formation of urine (ultra-filtration of blood, active reabsorption of ions, secretion of excretory substances, and passive reabsorption of water) – Accessory excretory organs of human. Explaining the roles of liver, lungs & skin.

Chapter 4 Biology and Human Welfare
Immunity and Human Diseases: How do human beings remain protected from disease-causing organisms? Who poses a threat to human health? How WASH can protect human beings from diseases?
Concept of immunity: Explaining the concepts of immunity, antigen, antibody, and immune response with a diagram. Concept of vaccine: Historical perspective – Edward Jenner and vaccination; different types of vaccine with examples. Pathogens and parasites causing human disease: Diarrhoea, malaria, diphtheria, pneumonia, tetanus, tuberculosis, dengue, Hepatitis A & B, AIDS (nature, symptoms, transmission) [In tabular form] Concept and components of WASH and its significance in eliminating disease burden – Developing knowledge and understanding about the importance of WASH and its impact on health and well being of human. Microbes in Human Welfare: How do microbes help us in our everyday lives?

  • Bio-control agents – Explaining the role of bacteria, viruses, and protozoa.
  • Bio-fertilizers – Explaining the role of bacteria, cyanobacteria, and mycorrhiza.

Chapter 5 Environment and its Resources
Ecology and Ecological Organization: What is ecology and how are the organisms organized in nature?
Ecology is the study of interactions between organisms and their environment including other organisms. In ecology interactions of organisms and their organizations are studied at the Individual level. Adaptation to light, humidity, and temperature with examples from the plant/animal world. Population-level: Concept of population and factors of population growth (natality mortality and migration). Community level: A Set of interacting populations is called a community and possible types of interactions among them are competition, predation, parasitism, and co-operation-explain with simple examples. Ecosystem level (Structural aspect): Abiotic factors: light, temperature, water, atmosphere, topography- mention only the names of different factors through the chart. Biotic factors communities including autotrophs and heterotrophs (consumers, decomposers, and transformers)-an elementary idea with examples with the help of diagrams, charts (Functional aspects): Explaining with examples- food chain, food web, energy flow, and nutrient cycle.

Natural Resources and its Sustainable Use: How different natural resources are intimately connected with our existence on earth?
Natural resources: forest, water, food, and energy – their use and overuse. Forest: Use (forest functions: watershed protection, atmospheric regulation, erosion control, local use, productive use); cause of deforestation and consequences. Water: Use (drinking, agriculture, industry, etc.); over-utilization and water scarcity (case study) Rainwater harvesting. Food: Source (Agriculture, horticulture, animal husbandry, fishery, alternate food sources); World food problem (case study) and its effect. Energy: Use, growing energy needs, wastage of energy/Energy conservation in daily life.

WBBSE Class 9 Life Science Blueprint for 3rd Summative Evaluation (Total Marks – 90)

Theme Group A Group B Group C Group D Total Marks Per Theme Total Number of Questions
MCQ
One Mark Per Question
VSA
One Mark Per Question
SA
Two Marks Per Question

LA
Five Marks Per Question

Chapter 1 Life and its Diversity 1 × 3 = 3 1 × 3 = 3 2 × 2 = 4 5 × 1 = 5 15 9
Chapter 2 Levels of Organization of Life 1 × 3 = 3 1 × 4 = 4 2 × 3 = 6 5 × 1 = 5 18 11
Chapter 3 Physiological Processes of Life 1 × 3 = 3 1 × 5 = 5 2 × 3 = 6 5 × 2 = 10 24 13
Chapter 4 Biology and Human Welfare 1 × 3 = 3 1 × 4 = 4 2 × 2 = 4 5 × 1 = 5 16 10
Chapter 5 Environment and its Resources 1 × 3 = 3 1 × 5 = 5 2 × 2 = 4 5 × 1 = 5 17 11
Total 15 21 24 30 90 54

Group A – MCQ: All questions are compulsory. There will be no alternative for MCQ.
Group B – VSA: Out of 26 questions, 21 questions are to be attempted. One (1) extra question is to be set from each theme. VSA questions may be of four types – answer in one word or one sentence, fill in the blanks, true/false, and match column A with column B. In column matching two points are to be kept in mind – (i) For each correct matching one (1) mark is allotted, (ii) There should be at least one (1) extra option in Column B.
Group C – SA: Out of 17 questions, 12 questions are to be attempted. One (1) extra question is to be set from each theme.
Group D – LA: 6 questions are to be attempted. Alternative questions from the same theme are to be set for each question. 5 marks can be given as a whole or can be divided into 3 + 2 or 2 + 3.

WBBSE Class 9 Solutions

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Comprehensive WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry can help students make connections between concepts.

Organic Chemistry Class 10 WBBSE Notes

Organic Chemistry : All carbon containing compounds except oxides of carbon, metal carbonates, bicarbonate, hydrogen cyanide and metallic cyanides are organic compounds and the chemistry of organic compounds is known as organic chemistry.

Organic compounds is a separate branch because organic compounds:

  • are large in number
  • show isomerism
  • are soluble in non-polar solvents
  • have complex structures
  • are bad conductors
  • show catenation
  • are made from small number of elements.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Role of organic compounds in life process : Organic compounds are intemately related to our daily life. In order to maintain the life process of our body the following process are required.

  • Intake of nutritional food for the growth the living body.
  • For repairing the depreciation of health.
  • Mobility
  • Reproduction

All these are fulfilled almost by all organic materials.

(i) The main ingredients in our food chart are classified of three types : carbohydrates (e.g. rice, wheat, sugar etc.), proteins (e.g. milk, fish, egg etc.) and fats (e.g. milk, oil, butter etc.)

(ii) These food materials are ultimately converted to single organic compounds in different metabolic process with the help of enzymes in our body.

(iii) Vitamin, an organic compound plays indirectly a very important role for maintaining the growth of our health.

(iv) For the translation and mobility of the animals, energy which is required is stored in our body. This energy is associated in an organic compound. This is known as ATP (adenosine triphosphate).

(v) Haemoglobin which is an organic compound an oxygen carrier supplies oxygen in the body.

Biomoleculcs: The molecules of compounds like carbohydrates, amino acids, proteins, vitamins, fats, RNA, DNA etc. which are essential for the continuation of life processes of biological species like plants and animals (including human beings) are known as biomolecules.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Some essential biomolecules are :

(i) Carbohydrates : These molecules are composed of carbon, hydrogen and oxygen. General formula of it is Cn(H2O)n. Carbohydrates. are the class of compounds that include polyhydric aldehydes, polyhydric ketones and large polymeric molecules that can be broken down to polyhydric aldehydes and ketones.

Carbohydrates which contain aldehyde groups are called aldose and the carbohydrate containing keto groups are called ketose.

Carbohydrates are mainly of three types :

(a) Monosaccharides : These are the simplest form and are not hydrolysed, e.g. glucose, fructose etc.

(b) Oligosaccharides: During hydrolysis they form fixed number (2-10) of more saccharides.
WBBSE Class 10 Physical Science Notes Chapter 8.5 Metallurgy 18

(c) Polysaccharides: These are the natural polymer of large number of mono saccharides. It has general formula (C6H10O5)n. e.g. starch, cellulose etc.
WBBSE Class 10 Physical Science Notes Chapter 8.5 Metallurgy 19

(ii) Proteins: Another class of compounds essential for living being are proteins. They contain carbon, hydrogen, oxygen and nitrogen. Proteins are consumed daily from our diet. During hydrolysis of proteins by acid, base or enzyme amino acids are produced.WBBSE Class 10 Physical Science Notes Chapter 8.5 Metallurgy 20
Proteins are of three types :
(a) Simple protein
(b) Conjugated protein
(c) Derived protein.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

(a) Types of simple protein :

  • Albumin: This type of protein can be isolated from egg, milk, wheat, serum etc.
  • Globulin: Proteins that are isolated from egg yolk, tissues, belong to this class of protein.
  • Glutemin: This type of protein is present in wheat, rice etc.
  • Protamin: This type of protein is present in wheat, barli etc.

(b) Conjugated protein : Examples of this type of protein are : nucleo protein, chromoprotein, glycoprotein, phosphoprotein, lipoprotein, metalloprotein.

(c) Derived protein : This type of proteins are available by the partial hydrolysis of protein of very high molecular weight by acid, base or enzyme to simpler protein.

(ii) Fats: Fats are composed of carbon, hydrogen and oxygen. These are made of glycerol and fatty aids. Fats may be of animal or vegetable origin.

Animal fats are found in : milk, cheese, butter, eggs, meat and oily fish.

Vegetable fats are found in : walnut, almonds, groundnut and coconut, mustard seeds, seasame seed etc.

Fat is a concentrated source of energy.

(iv) Vitamins: Vitamins are organic compounds containing carbon, hydrogen, oxygen and sometimes nitrogen and sulphur. Vitamins are necessary to carry out many vital processes. Their absence or deficiency causes many ailments and impairs the healthy living oi human being.

(v) Amino acids: Proteins are made of amino acids. These are the essential for living beings. Amino acids are the class of compounds containing amino group and carboxylic acid group. 1

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Amino acids are of three types :

Neutral amino acids : Amino acids containing the same number of amino and carboxylic acid groups are called neutral amino acids. These have one -NH2 group and one -COOH group. Total number  of amino acids in this group is 19. e.g. glycine (NH2CH2COOH), alanin [CH3CH(NH2)COOH] etc.

  • Basic amino acids : This type of amino acids have two -NH2 groups and one-COOH group, e.g. lysine, histidine etc.
  • Acidic amino acids : This type of amino acids have two -COOH groups ’• and one -NHZ group, e.g. aspartic acid, glutamic acid.

The essential amino acids are :

  • Valine
  • Lucine
  • Iso-lucine
  • Phenylalanine
  • Threonine
  • Methionine
  • Argenine
  • Lysine
  • Histidine
  • Tryptophan.                                                                                                              1

DNA (Deoxyribo nucleic acids): It is found in nucleus, mitochondria and chloroplast of the body cells. James Watson and Francis Crick were able to establish the structure of DNA in 1953. DNA molecule is double helical in nature. It contains three different chemical compositions.

  • Phosphoric acid
  • Deoxy ribose
  • Pyridine like base adenine and guanine, pyrimidine like base thymine and cytonine.

DNA has two strands of polynucleotides coiled around each other by hydrogen; bond in the form of double helix.

Function of DNA :

  • Transmission of herediatary characteristics.
  • Biosynthesis of proteins.

The genetic information for the cell is preserved in the sequence of this base in the DNA molecule. When a cell divides, DNA molecules replicate and make exact copies of themselves so that daughter cell will have identical DNA to that of parent cell.

RNA (Ribonucleic acid): RNA molecule is single stranded, containing 1 ribose, phosphoric acid and uracil as the nitrogenenous base. RNA plays a very Vital role in life process. RNA carries the message of DNA and acts accordingly.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Type of RNA : (a) mRNA (b) tRNA (c) rRNA. RNA(tRNA, mRNA) helps synthesis of polypeptides, the intermediates of proteins.

Bonding In organic compounds Electronic configuration of carbon shows that the number of electrons available in the outermost orbit is 4. The outermost electrons can only be capable to form covalent bond by sharing and pairing of its electrons with that of other element. So, valency of carbon becomes 4.

Catenation : The property by virtue of which carbon forms covalent linkage amongst them to form stable carbon chains is knoun as catenation. Catenation is an unique property of carbon. As a result of catenation, carbon can form innumerable chemical species with the supplement in various ways by the necessary addition of other elements like H, O, N, P, S, halogens etc.

Difference between organic and inorganic compounds :

Organic Compounds Inorganic Compounds
(i) Catenation property of carbon atoms and its effect : The catenation property of carbon atoms among themselves and other atoms gives rise to limitless number of organic compounds with strain chains and rings of carbon atoms. (i) Due to absence of catenetion property of its atoms, the number of inorganic compounds formed by the rest erf the elements in not so large.
(ii) Class similarity : Organic compounds can be easily classified into different groups with certain similar characteristic properties. (ii) In organic compounds cannot generally be classified into such groups with similar characteristics.
(iii) Thermal stability : Organic
compounds are in general, thermally unstable and decompose at higher temperature.
(iii) These are more or less thermally stable., These can tolerate comparatively higher temperatures without decomposition.
(iv) Bonding: Organic compounds are formed through covalent bonding in their molecules. (iv) These compounds are generally formed by eledrovalent or ionic bonding in their molecules.
(v) Melting and boiling points: As these compounds are covalent in nature, so they have comparatively lower melting and boiling points. (v) As these compounds are ionic in nature, so they have high melting and boiling points.
(vi) Solubility: These are soluble in organic solvents like alcohol, ether, benzene etc. but generally insoluble in water. (vi) These are soluble in ionising solvents like water but are generally insoluble in organic solvents.
(vii) Structural characteristics: They have widely varying structural forms, from simple chain structure to complex ring. (vii) They have mostly simple structure.
(viii) Isomerism: Different types of isomerism often occur in organic compounds. (viii) Isomerism is practically unknown in inorganic compounds.
(ix) Electrolytic character: These are generally non-electrolytes (ix) Inorganic compounds are general electrolytes.

Classification of organic compounds :
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 3

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Functional group : The groups which are responsible to characterise the compounds are Known as functional group.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 2

Homologous series : It is a group of compounds in which the various members have similar chemical properties, possess the same functional group and can be represented by the same general formula. The different members of a homologous series are called homologous and the phenomenon is called homology.

Constitutional or Structural Isomerism : The phenomenon in which two or more different compounds obviously having different physical and chemical properties possess the same molecular formula but different molecular structures due to the arrangements of the constitutional or structural isomerism.

Types of structural isomerism : Three types

(a) Chain isomerism; The compounds of the same class, with the same molecular formula, have chain isomerism due chain carbon atoms.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 4

(b) Position isonierism : The compounds of the same dass, with the same molecular formula, have position isomerism due to the position of functional groups.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 5

(c) Functional group isomerism : The compounds of the same class, with the same molecular formula, have functional group isomerism due to different functional groups.
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 6

Hydrocarbons : Hydrocarbons are organic compounds containing only carbon and hydrogen atoms in their molecules.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Types of hydrocarbons: Hydrocarbons are divided into two classes, namely

  • Saturated hydrocarbons
  • Unsaturated hydrocarbons.

Alkane : Open chain saturated hydrocarbons are known as alkanes. General formula of these compounds are : CnH2n+2 (n = integers)

Carbon atoms of these compounds are linked by single covalent bonds. Hy­drogen atoms of these compounds are also linked to one or more carbon atoms by a single covalent bonds.

Saturated hydrocarbon molecules do not contain any formal functional group and as such exhibit very little chemical activity. These are therefore known as paraffins.

Methane: Methane is the first member of the hydrocarbons of the alkane series. It is a colourless gas with molecular formula CH4.

Source:
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 7

(ii) Main source of methane is the natural gas. It is formed in nature in bio­logical decay of plants of swamps and marshes. Methane is called marsh gas. A little phosphine (PH3) and phosphorous dihydride (P2H4) accompany the methane gas and make it spontaneously inflammable. So, it often burns with flashes of flame over marshes. This is well known as ‘will-O-the-wisp’. It is just a natural phenomenon.

Chemical properties:
(i) Burning of methane: It burns in air or oxygen when ignited, and is oxidised to carbon dioxide and water with the evalution of heat.
CH4+2O2 = CO2 + H2O + 213 kcal/ molecule.

(ii) Substitution reaction : It undergoes substitution reaction. The first step of the reaction is :
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 8

Methane: A green house gas: Like carbon dioxide, water vapour etc. methane is known as a green house gas (contribution 19%) because it is capable to absorb visible light from sun-rays and keep the earth surface and its surrounding warm.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Uses of methane:

  • It is used as a domestic and industrial fuel by burning in gas-stoves. Almost 40% by volume of methane is present in coal gas.
  • It is used in the large-scale production of carbon black which is largely
    used for making printers’ ink, paints, typewriter, ribbon, motor tyres etc.
  • It is now used as a source of hydrogen for the synthesis of NH3.
  • It is used for the manufacture of methanol, chloromethane, chloroform etc.

Alkene: An alkene is an unsaturated aliphatic hydrocarbon with a double bond in-between two adjacent carbon atoms of its molecule.

General formula of alkene : CnH4 (where n is an integer)

Ethylene [or, Ethene]
The molecular formula of ethylene is C2H4 which can be written as CH2 = CH2.
It i colourless gas.

Source :
(i)
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 9
(ii) It is present in very small amount in coal gas.
(iii) Natural gas rich in methane when ignited at 1400°C — 1500°C at normal pressure, acetylene is obtained after cooling.
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 10

Chemical reaction :
(i) Addition reaction with hydrogen:
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 11
(ii) Addition reaction with bromine :
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 12
Uses of acetylene :

  • As an illuminant acetylene is used in acetylene lamp.
  • It is used as an oxyacetylene flame 2700°C, for cutting and welding iron plates and sheets.
  • It is used for the preparation of acetaldehyde, acetic acid, ethyl alcohol, acetone etc.
  • Acetylene is used for the preparation of weston, a solvent used in industry.
  • It is used for the preparation of synthetic rubber and plastics.
  • It is used as an anaesthatic agent.

Polymer : There are some organic molecules of low molecular weight, a large number of which join with one another repeatedly to produce a very big molecule of high molecular weight. The small molecules are known as monomers and the resulting large molecules are known as p tymers.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Some common polymers :
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 13

Hazards of using polymer materials in our environment :

  • Polythene, PVC, synthetic rubber after use are left anywhere else. Tyre used in the wheel of a vehicles are also thrown in the dustbin or these are burnt out. These materials have no natural decay in the soil by bacteria.
  • As a result there is a dumping of plastic materials and creates an environ­ment pollution.
  • It destroys the soils where it is dumping.
  • The plastic materials left in hills and mountain, is the cause of landslide.
  • Tyre prepared from synthetic rubber when left in air produces free radicals in presence of sunlight which is cancer producer.

Possible alternatives to avoid the hazards :

  • To get relief from these, limited uses are desirable
  • Now-a-day some reagents are added to plastic materials so that they would not create any problem or hazard to mankind.
  • Bags made to cloth, paper, jute should be used instead of polythene bags.

IUPAC (International Union of Pure and Applied Chemistry, 1957) nomenclature simple organic compounds :

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 14
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 15
Polymerisation: The process or technique through which monomer units combine to give a polymer is known as polymerisation.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Biodegradable polymers : The polymers that can be dissociated into small segments enzymes (produced by microorganisms) are called biodegradable polymers.

Example :
(i) PHBV (poly β-hydroxy butyrate co-β-hydroxy-valerate)
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 16

LPG (Liquified Petroleum Gas) : In refinning the crude petroleum, the gaseous products thus obtained the hydrocarbons of lower molecular weight after purification of these gaseous mixtures if there are cooled at hith pressure and low temperature, these are all condensed to liquidand. The liquid is known as Liquified Petroleum Gas (LPG).

Types of LPG :

  • Heavier grade LPG (80-90%) : C4-hydrocarbon (Butane, Isobutane, butene)
  • Lighter grade LPG (90%) : C3 hydrocarbon (Propane and propene, 10% C4-hydrocarbon (Butane and butene) 2% Ethane and ethylene.

Calorific value : Amount of heat energy produced by the complete com­bustion of one gram of the fuel is known as its calorific value.
Calorific value of LPG ; 29500 kcal/m3

CNG (Compressed Natural Gas):
It is compressed natural gas. It contains mainly methane. It has calorific value 21300 Btu/Ib

Uses of Ethanol:

  • Ethanol (C2H5OH) is used for drinking purpose.
  • Ethanol is widely used as a solvent.
  • Ethanol burns of give carbon dioxide and water and thus can be used as fuel.
  • Ethanol is used as antifreeze.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Physical properties of Ethanol :

  • It is colourless liquid having a sweet smell.
  • It is highly soluble in water.
  • It is volatile and inflammable.
  • It is neutral and it does not change the colour of litmus solution.

Reaction of Ethanol :

(i) Reaction with sodium (active metal): Ethanol reacts with sodium, to form sodium ethoxide and hydrogen.
2C2H5OH + 2Na → 2C2H5ONa + H2

(ii) Reaction of ethanol with cone. H2SO4 for dehydration :
Ethanol reacts with cone. H2SO4 at about 170°C to form ethylene.
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 18

Uses of acetic acid (CH3COOH)

  • It is used as an aid in cooking and for making pickles as also a preservative of fish, meat, vegetable etc. as vinegar (6-8% water solution of acetic acid)
  • It is used to prepare white paint.
  • It is used to concentrate the latex of leather.

Reactions of acetic acid :

(i) Reaction of acetic acid with NaHCO3 : During reaction of acetic acid with NaHCO3, sodium acetate, carbon dioxide and water are produced.
CH3COOH + NaHCO3 → CH3COONa + CO2↑+ H2O

(ii) Reaction of acetic acid with NaOH : Acetic acid reacts with NaOH to form sodium acetate and water.
CH3COOH + NaOH → CH3COONa + H2O

(iii) Reaction of acetic acid with C2H5OH : This reaction is called esterifi­cation. During this reaction ethyl acetate and water are produced.
WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry 17

Toxicity of Methanol : Methanol has a high toxicity in human. If as little as 10 mL of pure methanol is ingested, for example, it can break down into formic acid, which can cause permanent blindness by destruction of the opti nerve and 30 mL is potentially fatal, although the median lethal dose is typically 100 mL. Toxic effects take hours to start and effective antidotes can often prevent permanent damage.

WBBSE Class 10 Physical Science Notes Chapter 8.6 Organic Chemistry

Methanol is toxic by two mechanisms. First methanol (whether it enters the body by ingestion, inhalation or absorption through the skin) can be fatal due to its CNS depressant properties in the same manner as ethanol poisoing. Second, in a process of toxication, it is metabolized to formic acid (which is present as the formate ion) via formaldehyde in a process initiated by the enzyme alcohol dehydrogenase in the liver.

Methanol is converted to formal­dehyde via alcohol dehydrogenase (ADH) and formaldehyde is converted to formic acid (formate) via aldehyde dehydrogenase (ALDH). The conversion to formate via ALDH proceeds completely, with no detectable formaldehyde remaining.

Formate is toxic because it inhibits mitochondrial cytochrome C oxides, causing the symptoms of hypoxia at the cellular level, and also caus­ing metabolic acidosis, among a variety of other metabolic disturbances. So methanol is highly toxic and causes blindness insanity and even death. Ethanol is non-toxic but when drunk, it produces physiological effect and disturbs the brain activities.

Denatured spirit : Alcohol used for making beverages is highly taxed but the ethyl alcohol supplied to the chemical laboratories and industries is very cheap.

To make it unfit for drinking purposes, industrial alcohol is mixed with poisonous substance like methanol, pyridine etc. The process is known as denaturing and the product is called denatured alcohol. The ethylalcohol mixed with the methanol is called methylated spirit.