Plant Physiology MCQ:
1. Water potential is equal to___________
a) Ts + O.P
b) = T.P.
c) xl’p + Y
d) Zero
Answer: d) Zero
2. Transpiration is least in_____
a) good soil moisture
b) high wind velocity
c) dry environment
d) high atmospheric humidity.
Answer: d) high atmospheric humidity.
3. Phenyl mercuric acetate (PMA) results in_________
a) reduced photosynthesis
b) reduced transpiration
c) reduced respiration
d) killing of plants.
Answer: b) reduced transpiration
4. Stomata open and close due to_______
a) circadian rhythm
b) genetic clock
c) pressure of gases inside the leaves
d) turgor pressure of guard cells.
Answer: d) turgor pressure of guard cells.
6. Phytochrome is involved in________
a) phototropism
b) photorespiration
c) photoperiodism
d) geotropism
Answer: c) photoperiodism
7. Which of the following is responsible for the opening and closing of stomata in plants?
a) Chlorophyll
b) Gibberellin
c) Abscisic acid
d) Auxin
Answer: c) Abscisic acid
8. What is the primary function of auxins in plants?
a) Stimulating stem elongation
b) Promoting root growth
c) Inducing flowering
d) Enhancing photosynthesis
Answer: a) Stimulating stem elongation
9. Which of the following pigments is responsible for the red coloration of leaves in autumn?
a) Chlorophyll
b) Carotenoids
c) Anthocyanins
d) Xanthophylls
Answer: c) Anthocyanins
10. Phytohormones are________
a) chemical regulation of flowering
b) chemical regulation secondary growth
c) hormones regulating growth from seed to adulthood
d) regulators synthesized by plants and influencing physiological processes.
Answer: d) regulators synthesized by plants and influencing physiological processes.
11. Highest auxin concentration occurs__________
a) in growing tips
b) in leaves
c) at the base of plant organs
d) in the xylem and phloem.
Answer: a) in growing tips
12. Kranz’s anatomy is typical of__________
a) C4 plants
b) C3 plants
c) C2 plants
d) CAM plants
Answer: a) C4 plants
13. Which of the following processes involves the conversion of light energy into chemical energy in plants?
a) Transpiration
b) Respiration
c) Photosynthesis
d) Translocation
Answer: c) Photosynthesis
14. Which of the following is not a factor that affects the rate of photosynthesis in plants?
a) Temperature
b) Light intensity
c) Carbon dioxide concentration
d) Soil pH
Answer: d) Soil pH
15. Which of the following plant hormones is responsible for initiating the formation of roots in cuttings?
a) Cytokinins
b) Ethylene
c) Abscisic acid
d) Auxins
Answer: d) Auxins
16. What is the primary function of gibberellins in plants?
a) Inhibiting stem elongation
b) Promoting leaf growth
c) Promoting seed germination
d) Regulating stomatal closure
Answer: c) Promoting seed germination
17. Which of the following is a key component of the electron transport chain during photosynthesis?
a) NADP+
b) ATP
c) CO2
d) H2O
Answer: a) NADP+
18. Which of the following is responsible for transporting water and nutrients from the roots to the leaves in plants?
a) Xylem
b) Phloem
c) Stomata
d) Epidermis
Answer: a) Xylem
19. Which of the following is a plant hormone that is involved in promoting cell division and differentiation?
a) Gibberellin
b) Ethylene
c) Cytokinin
d) Abscisic acid
Answer: c) Cytokinin
20. Which of the following is the process by which plants release water vapor through stomata?
a) Osmosis
b) Transpiration
c) Respiration
d) Photosynthesis
Answer: b) Transpiration
21. Which of the following pigments is responsible for the green color of plants?
a) Chlorophyll
b) Carotenoids
c) Anthocyanins
d) Xanthophylls
Answer: a) Chlorophyll
22. Which of the following is the process by which green plants convert light energy into chemical energy?
a) Respiration
b) Photosynthesis
c) Transpiration
d) Translocation
Answer: b) Photosynthesis
23. Which of the following is the primary site of photosynthesis in a plant cell?
a) Mitochondria
b) Chloroplasts
c) Nucleus
d) Endoplasmic reticulum
Answer: b) Chloroplasts
24. Which of the following is a plant hormone that stimulates cell elongation and regulates phototropism and gravitropism?
a) Auxin
b) Gibberellin
c) Cytokinin
d) Abscisic acid
Answer: a) Auxin
25. Which of the following is the process by which plants take in carbon dioxide from the atmosphere and release oxygen?
a) Respiration
b) Photosynthesis
c) Transpiration
d) Translocation
Answer: b) Photosynthesis
26. Which plant pigments are responsible for the red, purple, and blue colors of flowers and fruits?
a) Chlorophyll
b) Carotenoids
c) Anthocyanins
d) Xanthophylls
Answer: c) Anthocyanins
27. Which of the following is a plant hormone that inhibits cell growth and promotes seed dormancy?
a) Auxin
b) Gibberellin
c) Cytokinin
d) Abscisic acid
Answer: d) Abscisic acid
28. Which of the following is the process by which plants convert glucose into energy in the presence of oxygen?
a) Respiration
b) Photosynthesis
c) Transpiration
d) Translocation
Answer: a) Respiration
29. In C3 and C4 plants, primary carboxylation takes place with the help of_________
a) PEP carboxylase and pyruvate carboxylase
b) RuBP carboxylase and PEP carboxylase
c) PEP carboxylase and RuBP carboxylase
d) RuBP carboxylase and pyruvate carboxylase
Answer: b) RuBP carboxylase and PEP carboxylase
30. The fundamental feature of Kranz Anatomy of C4 plants is_____________
a) Presence of agranal chloroplasts in bundle sheath cells and granal chloroplasts in mesophyll cells
b) Presence of granal chloroplasts in bundle sheath cells and agranal chloroplasts in mesophyll cells
c) Presence of chloroplasts in epidermal and mesophyll cells
d) Presence of agranal chloroplasts in both mesophyll and bundle sheath cells
Answer: a) Presence of agranal chloroplasts in bundle sheath cells and granal chloroplasts in mesophyll cells