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
One Mark Per Question
One Mark Per Question
Two Marks Per Question

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

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