This set of Plant Biotechnology Multiple Choice Questions & Answers (MCQs) focuses on “Plant Physiology”.
1. The process by which green plants make their own food is called as ___________
a) Respiration
b) Oxidation and reduction
c) Solarisation
d) Photosynthesis
View Answer
Explanation: Photosynthesis is the process by which green plants make their own food using sunlight and water. Respiration is the process by which plants reduces food and releases oxygen.
2. Which ions help in the photolysis of water during the light reaction?
a) Mn++, Ca++
b) Mg++, Zn++
c) Mn++, Zn++
d) Cl–, Mg++
View Answer
Explanation: During light reaction, photolysis of water is catalyzed by an enzyme complex that contains manganese and calcium and is present in the photosystems located in the thylakoid membrane of the chloroplast.
3. In C3 and C4 plants, primary carboxylation occurs with the help of which enzyme respectively?
a) PEP carboxylase and RuBP carboxylase
b) RuBP carboxylase and pyruvate carboxylase
c) Pyruvate carboxylase and PEP carboxylase
d) RuBP carboxylase and PEP carboxylase
View Answer
Explanation: RuBP carboxylase helps in primary carboxylation in C3 plants and PEP carboxylase helps in primary carboxylation in C4 plants. Pyruvate carboxylase catalyzes the formation of oxaloacetic acid from pyruvate.
4. In the light reaction, electron lost by PSII is regained from which molecule?
a) CO2
b) O2
c) H2O
d) PSII
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Explanation: H2O is the molecule that splits into 2H+, O2, and electron and helps PSII to regain its lost electron. The electron from PSII is transported to the first electron acceptor and then to the next acceptor following Z scheme.
5. The point at which the rate of photosynthesis is equal to the rate of respiration is called _____
a) Compensation point
b) Equivalence point
c) Respiratory quotient
d) Photosynthetic quotient
View Answer
Explanation: Compensation point is the point at which the rate of photosynthesis is equal to the rate of respiration. Respiratory quotient is the ratio of the amount of CO2 used to the amount of O2 used.
6. Pigment system I functions independently in _________
a) Non-cyclic photophosphorylation
b) Cyclic photophosphorylation
c) Photolysis
d) Oxidative phosphorylation
View Answer
Explanation: Both PSI (P700) and PSII (P680) take part in Non-cyclic photophosphorylation whereas only PSI takes part in cyclic phosphorylation. Non-cyclic photophosphorylation is also known as Z-scheme.
7. Name the first product of the C4 pathway.
a) Phosphoglyceraldehyde
b) Dihydroxyacetone phosphate
c) Oxaloacetic acid
d) Pyruvate
View Answer
Explanation: Oxaloacetic acid is the first product of C4 pathway whereas is the phosphoglyceraldehyde first product of C3 pathway. The first stable product formed is OAA which is a 4-carbon compound that is why the pathway is known as C4 pathway.
8. During the light phase of photosynthesis ______ is oxidized and ______ is reduced respectively.
a) Water and NADP
b) CO2 and water
c) NADP and water
d) NADPH2 and CO2
View Answer
Explanation: During the light phase, water is oxidized and the released hydrogen is accepted by NADP which gets reduced to NADPH2 whereas during the dark phase, NADPH2 gets oxidized and transfer its hydrogen to CO2 which is reduced to carbohydrate.
9. During the dark phase of photosynthesis ______ is oxidized and ______ is reduced respectively.
a) Water and NADP
b) CO2 and water
c) CO2 and NADPH2
d) NADPH2 and CO2
View Answer
Explanation: During the dark phase, NADPH2 gets oxidized and transfer its hydrogen to CO2 which is reduced to carbohydrate whereas during the light phase, water is oxidized and the released hydrogen is accepted by NADP which gets reduced to NADPH2.
10. During the Calvin cycle in the C4 plant, the source of CO2 is ___________
a) Oxaloacetic acid
b) Malic acid
c) Phosphoenolpyruvate
d) Glucose
View Answer
Explanation: Malic acid undergoes carboxylation and produces CO2 during the Calvin cycle in a C4 plant whereas glucose is reduced to pyruvate during the glycolysis process of respiration.
11. Which of the following plant do not perform photosynthesis?
a) Maize
b) Corn
c) Sugarcane
d) Cuscuta
View Answer
Explanation: Cuscuta plant does not perform photosynthesis because it is a parasite that is, it feeds on another organism for its food whereas maize, corn and sugarcane belongs to the category of C4 plants.
12. What is the quantum yield of photosynthesis?
a) 8%
b) 13%
c) 8.5%
d) 12.5%
View Answer
Explanation: The quantum yield of photosynthesis is derived from the intensity of sunlight and the rate of photosynthesis. The quantum requirement of photosynthesis is 8% whereas the quantum yield of photosynthesis is 12.5% (1/8*100).
13. In C4 plants, synthesis of glucose occurs in __________
a) Mesophyll cells
b) Bundle sheath cells
c) Palisade cells
d) Spongy cells
View Answer
Explanation: Glucose synthesis occurs in bundle sheath cells of C4 plants whereas it occurs in mesophyll cells in C3 plants. Palisade cells are present in the mesophyll of leaves and helps in absorption of light.
Spongy cells form a layer below the palisade cells in the leaf.
Sanfoundry Global Education & Learning Series – Plant Biotechnology.
To practice all areas of Plant Biotechnology, here is complete set of 1000+ Multiple Choice Questions and Answers.
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