MCQs on Mineral Nutrition – Class 11 Biology NCERT
MCQs on Mineral Nutrition – CBSE Class 11 Biology (Unit IV | NCERT-Based)
CBSE Class 11 Biology – MCQs with Answers and Explanations
Unit IV: Plant Physiology
Topic: Mineral Nutrition
Section A: Essential Mineral Elements & Criteria (Q1–Q10)
Q1. Mineral nutrition refers to the study of:
A. Organic food in plants
B. Photosynthesis
C. Inorganic nutrients required by plants
D. Water absorption only
Answer: C
Explanation: Mineral nutrition deals with inorganic elements essential for plant growth and metabolism.
Q2. Which scientist proposed the criteria for essentiality of mineral elements?
A. Darwin
B. Sachs
C. Arnon and Stout
D. Liebig
Answer: C
Explanation: Arnon and Stout (1939) proposed criteria to identify essential mineral elements.
Q3. Which of the following is NOT a criterion for essentiality?
A. Element must be required for normal growth
B. Element cannot be replaced by another
C. Element must be directly involved in metabolism
D. Element must be present in large quantity
Answer: D
Explanation: Essential elements may be required in trace amounts, not necessarily large quantities.
Q4. Which element is a part of chlorophyll molecule?
A. Nitrogen
B. Iron
C. Magnesium
D. Calcium
Answer: C
Explanation: Magnesium is the central atom of chlorophyll.
Q5. Macronutrients are required by plants in:
A. Trace amounts
B. Very small quantities
C. Large quantities
D. Equal quantities
Answer: C
Explanation: Macronutrients are needed in relatively large amounts.
Q6. Which of the following is a micronutrient?
A. Nitrogen
B. Phosphorus
C. Potassium
D. Zinc
Answer: D
Explanation: Zinc is required in trace amounts, hence a micronutrient.
Q7. Which element is required for cell wall stability?
A. Magnesium
B. Calcium
C. Potassium
D. Sulphur
Answer: B
Explanation: Calcium provides structural integrity to cell walls.
Q8. Which element is a component of amino acids and proteins?
A. Potassium
B. Nitrogen
C. Magnesium
D. Iron
Answer: B
Explanation: Nitrogen is essential for amino acids, proteins, and nucleic acids.
Q9. Which of the following is a non-mineral essential element?
A. Iron
B. Zinc
C. Carbon
D. Magnesium
Answer: C
Explanation: Carbon is obtained from CO₂, not from soil minerals.
Q10. How many essential elements are recognized for plants (NCERT)?
A. 14
B. 16
C. 17
D. 20
Answer: C
Explanation: Plants require 17 essential elements for normal growth.
Section B: Macronutrients – Roles & Deficiency (Q11–Q25)
Q11. Nitrogen deficiency causes:
A. Yellowing of older leaves
B. Necrosis of young leaves
C. Leaf fall only
D. Root swelling
Answer: A
Explanation: Nitrogen is mobile; deficiency symptoms appear in older leaves as chlorosis.
Q12. Which element is involved in ATP synthesis?
A. Potassium
B. Sulphur
C. Phosphorus
D. Calcium
Answer: C
Explanation: Phosphorus is a key component of ATP.
Q13. Potassium deficiency results in:
A. Reduced transpiration
B. Necrosis of leaf margins
C. Increased chlorophyll
D. Root hair formation
Answer: B
Explanation: Potassium deficiency causes leaf margin necrosis.
Q14. Which element activates many enzymes?
A. Calcium
B. Magnesium
C. Potassium
D. Iron
Answer: C
Explanation: Potassium acts as an enzyme activator.
Q15. Sulphur is a component of:
A. Chlorophyll
B. Nucleic acids
C. Vitamins and amino acids
D. Cell wall
Answer: C
Explanation: Sulphur is present in cysteine, methionine, and vitamins.
Q16. Magnesium deficiency causes:
A. Leaf curling
B. Interveinal chlorosis
C. Necrosis of buds
D. Wilting
Answer: B
Explanation: Magnesium deficiency leads to interveinal chlorosis in older leaves.
Q17. Which element maintains osmotic balance in cells?
A. Nitrogen
B. Calcium
C. Potassium
D. Phosphorus
Answer: C
Explanation: Potassium helps maintain osmotic balance and turgidity.
Q18. Calcium deficiency affects:
A. Young tissues
B. Old leaves
C. Mature stems
D. Fruits only
Answer: A
Explanation: Calcium is immobile; deficiency appears in young tissues.
Q19. Which element is required for synthesis of proteins and coenzymes?
A. Nitrogen
B. Sulphur
C. Magnesium
D. Potassium
Answer: B
Explanation: Sulphur is involved in protein and coenzyme formation.
Q20. Chlorosis refers to:
A. Leaf fall
B. Tissue death
C. Yellowing of leaves
D. Curling of leaves
Answer: C
Explanation: Chlorosis is due to loss or reduction of chlorophyll.
Q21. Necrosis is the symptom of:
A. Excess growth
B. Tissue death
C. Increased chlorophyll
D. Cell division
Answer: B
Explanation: Necrosis refers to death of plant tissues.
Q22. Which macronutrient is a part of nucleic acids?
A. Nitrogen
B. Potassium
C. Calcium
D. Magnesium
Answer: A
Explanation: Nitrogen is a constituent of DNA and RNA.
Q23. Which nutrient deficiency causes delayed flowering?
A. Nitrogen
B. Phosphorus
C. Potassium
D. Calcium
Answer: B
Explanation: Phosphorus deficiency delays flowering and seed formation.
Q24. Which element maintains membrane permeability?
A. Potassium
B. Calcium
C. Nitrogen
D. Sulphur
Answer: B
Explanation: Calcium stabilizes cell membranes.
Q25. Mobile elements show deficiency symptoms in:
A. Young leaves
B. Root tips
C. Older leaves
D. Flowers
Answer: C
Explanation: Mobile nutrients are translocated to young parts, so deficiency appears in older leaves.
Section C: Micronutrients – Roles & Deficiency (Q26–Q40)
Q26. Which micronutrient is a component of cytochromes?
A. Copper
B. Zinc
C. Iron
D. Manganese
Answer: C
Explanation: Iron is part of cytochromes and electron transport proteins.
Q27. Iron deficiency causes:
A. Chlorosis of young leaves
B. Necrosis of old leaves
C. Leaf fall
D. Root damage
Answer: A
Explanation: Iron is immobile; deficiency appears in young leaves.
Q28. Which element is required for nitrogen fixation?
A. Copper
B. Iron
C. Molybdenum
D. Zinc
Answer: C
Explanation: Molybdenum is essential for nitrogenase enzyme.
Q29. Which micronutrient activates carbonic anhydrase?
A. Iron
B. Zinc
C. Copper
D. Boron
Answer: B
Explanation: Zinc activates carbonic anhydrase.
Q30. Boron deficiency affects:
A. Root elongation
B. Cell wall formation
C. Stomatal opening
D. Chlorophyll synthesis
Answer: B
Explanation: Boron is required for cell wall synthesis and membrane function.
Q31. Which micronutrient is involved in photolysis of water?
A. Zinc
B. Copper
C. Manganese
D. Iron
Answer: C
Explanation: Manganese is involved in splitting of water during photosynthesis.
Q32. Copper deficiency causes:
A. Chlorosis
B. Dieback of shoots
C. Leaf fall
D. Root hair damage
Answer: B
Explanation: Copper deficiency leads to dieback of young shoots.
Q33. Which micronutrient is a component of plastocyanin?
A. Iron
B. Zinc
C. Copper
D. Boron
Answer: C
Explanation: Copper is part of plastocyanin involved in electron transport.
Q34. Which element helps in pollen germination?
A. Zinc
B. Boron
C. Iron
D. Molybdenum
Answer: B
Explanation: Boron plays a role in pollen tube growth.
Q35. Micronutrients are required in:
A. Kilograms
B. Grams
C. Milligrams
D. Trace amounts
Answer: D
Explanation: Micronutrients are needed in very small quantities.
Q36. Which element deficiency causes rosetting?
A. Iron
B. Zinc
C. Calcium
D. Potassium
Answer: B
Explanation: Zinc deficiency leads to short internodes and rosetting.
Q37. Toxicity symptoms may occur due to excess of:
A. Macronutrients only
B. Micronutrients only
C. Both macro and micro
D. Water
Answer: C
Explanation: Excess of any nutrient can cause toxicity.
Q38. Excess manganese interferes with uptake of:
A. Nitrogen
B. Calcium, magnesium and iron
C. Potassium
D. Phosphorus
Answer: B
Explanation: Excess Mn competes with Ca, Mg, and Fe.
Q39. Which element is essential for synthesis of auxin?
A. Iron
B. Zinc
C. Copper
D. Boron
Answer: B
Explanation: Zinc is involved in auxin synthesis.
Q40. Which micronutrient deficiency causes chlorosis and necrosis together?
A. Iron
B. Boron
C. Manganese
D. Zinc
Answer: C
Explanation: Manganese deficiency causes interveinal chlorosis with necrotic spots.
Section D: Nitrogen Metabolism & Special Topics (Q41–Q50)
Q41. Atmospheric nitrogen is fixed mainly by:
A. Plants directly
B. Animals
C. Nitrogen-fixing bacteria
D. Fungi only
Answer: C
Explanation: Nitrogen is fixed by free-living and symbiotic bacteria.
Q42. Symbiotic nitrogen fixation occurs in root nodules of:
A. Cereals
B. Legumes
C. Bryophytes
D. Algae
Answer: B
Explanation: Legumes form symbiotic association with Rhizobium.
Q43. The enzyme nitrogenase requires:
A. Calcium
B. Iron and molybdenum
C. Zinc
D. Copper
Answer: B
Explanation: Nitrogenase is a Fe–Mo enzyme.
Q44. Which form of nitrogen is absorbed by plants most commonly?
A. N₂
B. NO₂⁻
C. NH₄⁺ and NO₃⁻
D. NO
Answer: C
Explanation: Plants absorb nitrogen mainly as nitrate and ammonium ions.
Q45. Ammonification converts:
A. Ammonia to nitrate
B. Nitrate to nitrite
C. Organic nitrogen to ammonia
D. Nitrogen gas to ammonia
Answer: C
Explanation: Ammonification releases ammonia from organic matter.
Q46. Nitrification involves conversion of:
A. N₂ to NH₃
B. NH₃ to NO₂⁻ and NO₃⁻
C. NO₃⁻ to NH₃
D. Organic nitrogen to nitrate
Answer: B
Explanation: Nitrification is carried out by Nitrosomonas and Nitrobacter.
Q47. Denitrification results in:
A. Loss of nitrogen from soil
B. Gain of nitrogen in plants
C. Increased fertility
D. Ammonia formation
Answer: A
Explanation: Denitrification converts nitrates to N₂ gas, reducing soil nitrogen.
Q48. Which pigment shows nitrogen deficiency early?
A. Carotene
B. Xanthophyll
C. Chlorophyll
D. Anthocyanin
Answer: C
Explanation: Nitrogen deficiency reduces chlorophyll synthesis.
Q49. Leghemoglobin is present in:
A. Leaves
B. Roots
C. Root nodules
D. Stem
Answer: C
Explanation: Leghemoglobin maintains low oxygen concentration for nitrogenase.
Q50. Mineral nutrition is essential for plants because it affects:
A. Growth only
B. Metabolism only
C. Reproduction only
D. All physiological processes
Answer: D
Explanation: Minerals influence growth, metabolism, enzyme activity, and reproduction.