Free Forms and Functions of Plants MCQs with Answers
272 Forms and Functions of Plants MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Plant nutrition and transport cover mineral uptake, photosynthesis, xylem movement of water and minerals, and phloem translocation of sugars. Plant growth regulators include auxins, gibberellins, cytokinins, abscisic acid and ethene, whose effects on cell division, elongation, dormancy, fruit ripening and tropic responses should not be confused with mineral nutrition.
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11. An enzyme that can stimulate the germination of barley seeds is:
- A. Invertase
- B. Amylase
- C. Lipase
- D. Protease
Explanation: Amylase breaks starch → maltose/glucose → energy for germination.
Correct answer: Amylase12. How does pruning help in making the hedge dense?
- A. Releases wound hormones
- B. Induces differentiation of new shoots
- C. Frees axillary buds from apical dominance
- D. Apical shoot grows faster
Explanation: Removes apical bud → axillary buds grow → hedge dense.
Correct answer: Frees axillary buds from apical dominance13. The ability of the Venus flytrap to capture insects is due to:
- A. Specialized muscle-like cells
- B. Chemical stimulation by prey
- C. Passive process
- D. Rapid turgor pressure changes
Explanation: Sudden turgor loss in specialized cells closes trap rapidly.
Correct answer: Rapid turgor pressure changes14. Differentiation of shoot is controlled by:
- A. High Auxin:Cytokinin Ratio
- B. High Cytokinin:Auxin Ratio
- C. High Gibberellin:Auxin Ratio
- D. High Gibberellin:Cytokinin Ratio
Explanation: High cytokinin-to-auxin ratio → shoot formation; high auxin → root formation.
Correct answer: High Cytokinin:Auxin Ratio15. Seed dormancy is due to the :
- A. Ethylene
- B. Abscisic Acid
- C. IAA
- D. Starch
Explanation: .ABA induces dormancy and prevents premature germination.
Correct answer: Abscisic Acid16. Dwarfness can be controlled by treating the plant with:
- A. Cytokinin
- B. Gibberellic Acid
- C. Auxin
- D. Antigibberellin
Explanation: GA stimulates stem elongation, flowering, and fruit development.
Correct answer: Gibberellic Acid17. Abscisic acid controls:
- A. Cell Division
- B. Leaf Fall and Dormancy
- C. Shoot Elongation
- D. Cell Elongation and Wall Formation
Explanation: ABA induces leaf abscission & seed dormancy under stress.
Correct answer: Leaf Fall and Dormancy18. Phototropic and geotropic movements are linked to:
- A. Gibberellins
- B. Enzymes
- C. Auxin
- D. Cytokinins
Explanation: Auxin distribution controls shoot bending toward light and root growth.
Correct answer: Auxin19. Which of the following movements is not related to auxin level?
- A. Bending of shoot towards light
- B. Movement of root towards soil
- C. Nyctinastic leaf movements
- D. Movement of sunflower head tracking the sun
Explanation: Nyctinasty is turgor-based, circadian-regulated, not auxin controlled.
Correct answer: Nyctinastic leaf movements20. Which of the following hormones can replace vernalisation?
- A. Auxin
- B. Cytokinin
- C. Gibberellins
- D. Ethylene
Explanation: GA induces flowering without cold treatment.
Correct answer: Gibberellins