Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 3.1B Mineral Nutrition offer valuable context and analysis.
WBBSE Class 9 Science Chapter 3.1B Question Answer – Mineral Nutrition
Very Short Questions and Answers : (1 mark for each question)
Question 1.
Which type of nutrients mainly take part in the structural formation of protoplasm?
Answer:
Macronutrients take part mainly in the structural formation of protoplasm.
Question 2.
Which type of elements act mainly as cofactors of enzymes?
Answer:
Micro elements mainly act as cofactors of enzymes.
Question 3.
What is the functional similarity between Fe and Cu in the life process of an organism?
Answer:
Both Fe and Cu take part in oxidation reduction process of photosynthesis and respiration.
Question 4.
What is the functional similarity between Zn and Mg in biochemical activities?
Answer:
Both Zn and Mg act as cofactors of enzymes.
Question 5.
What is chlorosis?
Answer:
The yellowing of leaves due to disintegration of chlorophyll, as a result of the absence of one or more essential elements, is called chlorosis.
Question 6.
Which metallic element is actively present in electron carriers like cytochrome and ferredoxin?
Answer:
Iron (Fe) is actively present in electron carriers like cytochrome and ferredoxin.
Question 7.
Mention a deficiency symptom of sulphur in patients.
Answer:
In case of sulphur deficiency, young twigs become weak.
Question 8.
Mention one metallic macronutrient and one micronutrient, essential for plants.
Answer:
Magnesium is a metallic macronutrient and iron is a metallic micronutrient, essential for plants.
Question 9.
Name any two gaseous macroelements essential for all living organisms.
Answer:
Oxygen and nitrogen are two gaseous macroelements essential for all living organisms.
Question 10.
Which macroelements take part in the structural formation of protoplasm?
Answer:
The macroelements which take part in the structural formation of protoplasm are C, H, O, N, P, Mg, and S.
Question 11.
Which macronutrient is essential for the formation of plasma membrane?
Answer:
Calcium is an essential macronutrient which helps in the formation of plasma membrane.
Short Questions and Answers : (2 marks for each question)
Question 1.
What is meant by macronutrients?
Answer:
The elements, that are required in larger quantities for growth, development and normal physiological activities of plants, are called macronutrients. Example-Carbon (C), Nitrogen (N), Phosphorus (P) etc.
Question 2.
What is meant by micronutrients?
Answer:
The elements, that are required in minute quantities for normal physiological activities of plants, are called micronutrients. Example – Molybdenum (Mo), Boron (B), Zinc (Zn) etc.
Question 3.
How are mineral nutrients associated with survival of plants?
Answer:
For normal growth, proper formation of cells and tissues and proper operation of all physiological functions, plants need different minerals. Minerals act as structural components of protoplasm, cofactors of various enzymes controlling several bio-chemical reactions within the cells etc. That is how mineral nutrients are associated with the survival of plants.
Question 4.
How do different elements take part in the formation of a plant cell?
Answer:
Various elements, such as C, H, O, S, Mg, P, N and Fe, play a prominent role in the formation of protoplasmic chemical constituents of a cell. All cellular matters are basically composed of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). Proteins need sulphur (S), nucleic acids need phosphorus (P), chlorophylls need magnesium (Mg) and middle lamella of cell needs calcium (Ca) other than C, H, O, and N.
Question 5.
Which elements play role in maintaining osmotic balance in plant cells?
Answer:
Different inorganic salts of potassium (K)and sodium (Na) play an important role in maintaining the osmotic balance of the cells in plants. The elements remain as chloride \(\left(\mathrm{Cl}^{-}\right)\), phosphate \(\left(\mathrm{PO}_4^{3-}\right)\), sulphate \(\left(\mathrm{SO}_4^{2-}\right)\) etc. which help to maintain the osmotic concentration within the plant cells.
Question 6.
How do salts play role in maintaining the pH of a cellular fluid?
Answer:
Certain ions, like phosphate \(\left(\mathrm{PO}_4^{3-}\right)\), bicarbonate \(\left(\mathrm{HCO}_3^{-}\right)\) and carbonate \(\left(\mathrm{CO}_3^{2-}\right)\) may act as buffers and thus resist marked change in pH. Thus, inorganic salts help to regulate pH of any cellular fluid.
Question 7.
What are the main functions of potassium in a plant body?
Answer:
The main functions of potassium in a plant body are as follows-
- It takes part in protein and carbohydrate synthesis.
- It acts as co-enzyme and helps in stomatal movement.
- Maintains normal growth and colour of the leaves.
Question 8.
What are the symptoms that occur due to the deficiency of potassium?
Answer:
The distinct symptoms that occur due to the deficiency of potassium are-
- discolouration of leaves,
- slow growth of roots and seeds
- curling of older leaves.
Question 9
Mention three importance of phosphorus in a plant body.
Answer:
Three importance of phosphorus in a plant body are as follows-
- It plays an important role in protein synthesis.
- It acts as component of ATP, NADP and membrane of cells and other organelles.
- It prevents premature shedding of leaves and blackening of fruits and leaves.
Question 10
Mention the importance of calcium in a plant body.
Answer:
The importance of calcium in a plant body are as follows-
- It helps in cell division by spindle formation and formation of middle lamella of the cell wall.
- It helps in nitrogen and carbohydrate metabolism.
- It maintains normal blooming of flowers.
Question 11.
What are the major roles of magnesium in a plant body?
Answer:
The main roles of magnesium in a plant body are as follows-
- It acts as the metallic constituent of chlorophyll.
- It acts as an enzyme activator.
- Prevents scorching and discolouration of the leaves.
Question 12.
What are the significance of boron in a plant hody?
Answer:
The significance of boron in a plant body are as follows-
- It helps in the formation and growth of leaves and flowers.
- It takes part in calcium and potassium metabolism and protein synthesis,
- It helps in the elongation of pollen tube.
Question 13.
What are the functions of zinc in plant body?
Answer:
The functions of zinc in plant body are as follows-
- It helps in the synthesis of auxins and certain proteins.
- It activates various enzymes as cofactors.
- It also maintains normal growth of the stems and roots.
Question 14.
What are the symptoms that occur due to deficiency of zinc?
Answer:
The distinct symptoms that occur due to deficiency of zinc are-
- retarded growth of roots, stems and leaves,
- delayed seed formation,
- discolouration of leaves.
Question 15.
What is the importance of manganese in a plant body?
Answer:
Importance of manganese in a plant body are as follows-
- It acts as an enzyme activator.
- It takes part in the chlorophyll and protein synthesis.
- It helps in the normal growth of shoots and prevents necrosis of leaves.
Question 16.
Mention the significance of sulphur as a mineral nutrient.
Answer:
The significance of sulphur are as follows:
- It acts as a major constituent of amino acids, vitamins and co-enzyme A.
- It helps in the formation of chlorophylls and development of roots.
- Sulphur prevents hardening of stems and helps in metabolism.
Question 17.
What is necrosis?
Answer:
The death of cells of certain areas of the plant body, due to the deficiency of any particular mineral nutrient (mainly Cl, Mn, Cu ) resulting in the drying up of those affected areas, is called necrosis.
Question 18.
Name the metallic elements which are essential for plants.
Answer:
The metallic elements which are essential for plants are-Magnesium (Mg), Potassium (K), Calcium (Ca), Manganese (Mn), Iron (Fe), Zinc (Zn), Copper (Cu), Molybdenum (Mo), Cobalt (Co), Nickel (Ni), Sodium (Na) etc.
Question 19.
Write the source of carbon (C), oxygen (O) and hydrogen (H) in plants.
Answer:
In plant body, source of carbon is the CO2 gas, present in atmosphere. Hydrogen is obtained from the water vapour present in atmosphere and also from the water present in soil. Oxygen is taken up by plants directly from the air.
Long Questions and Answers : (5 marks for each question)
Question 1.
Mention the general characteristic features of macronutrients. Write the characteristic features of micronutrients.
Answer:
Characteristic features of macronutrients
The general characteristic features of macronutrients are as follows-
- These elements are present in larger quantities (1-10 mg per g dry weight of plants, or more).
- They are mainly involved in the synthesis of structural components of the plant cells.
- They also participate in maintaining the osmotic potential of the plants.
Characteristic features of micronutrients
The characteristic features of micronutrients are as follows-
- The elements are present in minute quantities ( 0.1mg per g) dry weight of plant, or less).
- High concentrations of micronutrients may prove to be toxic for the plants.
- They mainly participate in electron transport mechanisms and act as cofactors for various enzymes.
Question 2.
Mention the general functions of different nutrients in plants.
Answer:
Functions of different nutrients in plants
The general functions of different nutrients in plants are as follows-
1. Formation of protoplast: Various nutrients, such as C, H, O, S, N, P, Mg and Fe play a prominent role in the formation of chemical constituents of protoplasm.
2. Structure of enzyme: Nutrients, such as Ca, Mg, K, Zn, Cl, Cu, Ni etc. are involved in the formation of various enzymes or act as co-factors.
3. Oxidation-reduction reaction: Flement such as Fe and Cu, take part in electron transfer and thus, bring about oxidation-reduction reaction.
4. Osmotic balance: Presence of inorganic salts (such as \(\mathrm{Cl}^{-}, \mathrm{PO}_4^{3-}, \mathrm{SO}_4^{2-}\) etc.) in the cell sap are involved in maintaining the osmotic balance of the cell.
5. Formation of chlorophyll: Elements, such as O, N, H, C and Mig play a prominent role in the formation of chlorophyll. Iron (Fe) helps in this process.
6. Buffer effect: Certain salts, like phosphates, bicarbonates and carbonates may act as buffers and thus, resist marked change in pH.
7. Growth: Mineral elements, such as Zn, Mn, B etc, maintain normal growth of stem and root.
Question 3.
Mention the importance of any five macronutrients in plants.
Answer:
Importance of any five macronutrients in plants
The importance of any five macronutrients in plants have been discussed below.
1. Phosphorus (P):
- Plays an important role in protein synthesis.
- It acts as a component of ATP, NADP and membrane of cells & other organelles.
- It prevents premature shedding of leaves, blackening of fruits & leaves.
2 Sulphur (S) :
- It is the major constituent of certain amino acids, vitamins & co-enzyme A.
- It helps in the formation of chlorophyll & development of roots.
- It also prevents hardening of stems and plays important role in growth and metabolism.
3. Potassium (K):
- It takes part in protein & carbohydrate synthesis.
- It acts as co-enzyme & helps in the stomatal movement.
- Potassium maintains normal growth & colour of leaves.
4. Calcium (Ca):
- It helps in cell division by spindle formation,
- It helps in nitrogen & carbohydrate metabolism.
- It helps in formation of cell membrane and the middle lamella of cell wall in plants.
5. Magnesium (Mg):
- It acts as primary metallic constituent of chlorophyll.
- It helps in enzyme activation.
- It prevents scorching discolouration of leaves.
- It helps in nucleic acid synthesis and controls fat and carbohydrate metabolism.
Question 4.
Mention the deficiency symptoms of the macronutrients phosphorus, sulphur and magnesium in plants. Mention the deficiency symptoms of the micronutrients copper, manganese and boron in plants.
Answer:
Symptoms due to deficiency of P, S and Mg:
The deficiency symptoms of phosporus, sulphur and magnesium are as follows-
1. Phosphorus (P):
- Leaves and stems turn bluish-green in colour,
- necrosis occurs in leaves,
- plants become weak and stunted.
2. Sulphur (S):
- Curling of leaves occurs followed by necrosis,
- nodule formation in leguminous plants is hampered,
- overall growth of plant is hampered.
3. Magnesium (Mg):
- Chlorosis of matured leaves occurs.
- retarded growth of plants is seen,
- carbohydrate formation is hampered.
Symptoms due to deficiency of Cu, Mn and B.
The deficiency symptoms of copper, manganese and boron are as follows-
1. Copper (Cu):
- Necrosis occurs in tender leaves
- nitrogen metabolism is hampered
- dieback disease (rotting) occurs in the tender portions of stems.
2. Manganese (Mn):
- Necrosis of leaves occurs
- leaves become yellowish, and intervenous chlorosis takes place.
3. Boron (B):
- Rotting of apical portions of stems and roots, followed by necrosis
- margins of leaves dry up and as a result the leaves curl up
- drought spot disease occurs in apples.
Question 5.
Mention the importance of different micronutrients in plants.
Answer:
Importance of different micronutrients in plants
The importance of different micronutrients in plants have been mentioned below.
1. Iron (Fe):
- It helps in the formation of chlorophyll & chromatin reticulum.
- It acts as structural element of electron carriers & helps in ion absorption.
2 Copper (Cu):
- It acts as structural component of some enzymes & helps in reduction of nitrates.
- It takes part in electron transportation in photosynthesis.
- It prevents necrosis of leaves in cereals & pulses.
3. Molybdenum (M0):
- It helps in the fixation & assimilation of nitrogen.
- It acts as cofactor for enzymes involved in nitrogen fixation.
- It helps in normal flowering & colouration of leaves.
- [It also helps in protein synthesis.
4. Zinc (Zn):
- It helps in the synthesis of auxins & certain proteins,
- It activates various enzymes by acting as cofactor.
5. Manganese (Mn):
- It acts as enzyme activator.
- Takes part in chlorophyll & protein synthesis.
- Prevents necrosis of leaves.
6 Boron (B):
- It helps in the formation and growth of flowers & leaves.
- Takes part in protein synthesis.
- Boron helps in the metabolism of calcium and potassium.
- It also helps in the elongation of pollen tube.
7. Chlorine (CI):
- Chloride ions, in the cell sap, helps in maintaining the osmotic balance of the cell,
- Helps in the opening and closing of stomata.
- takes a passive role in photosynthesis.
8 Nickel (Ni):
- Nickel is a component of some plant enzymes, most notably urease, which metabolises urea into ammonia.
- It also acts as a catalyst of enzymes, that help legumes to fix nitrogen.
Question 6.
Distinguish between macronutrients and micronutrients.
Answer:
Differences between macronutrients and micronutrients
| Features | macronutrients | micronutrients | ||
| 1. Necessity | These are needed in larger quantities for growth, development and different physiological activities of the cell | These are needed in very small quantities for growth, development and different physiological activities of the cell | ||
| 2. General function | Building ceil and different protoplasmic components | Mainly help in catalytic activities | ||
| 3. Effect of deficiency | Deficiency symptoms are very distinct and plants are adversely affected | Deficiency symptoms are often indistinct and plants are slightly affected | ||
| 4. Effect of excess intake | Excess nutrients are disposed without causing serious harm | Often cause harm to the plant | ||
| 5. Example | Oxygen, nitrogen, carbon etc. | Boron, molybdenum, manganese etc. | ||
Question 7.
What is ‘hydroponics’? Explain in a few sentences.
Answer:
Hydroponics
Hydroponics is defined as the subset of hydroculture and a method of growing plants using mineral nutrient solution, in water, but without soil.
Explanation:
Plants require several metallic and non-metallic elements for their normal healthy growth. Plants acquire these essential elements usually from the soil. But, scientists have experimentally proved that soil is not essential for the growth of plants. Only solutions, rich in mineral nutrients, are enough for this process. Thus, the process of cultivation of plants by placing roots in liquid nutrient solution, rather than in soil, and then observing their growth, is called ‘hydroponics.’ It is also called soilless growth of plants.