250+ TOP MCQs on General Features of Photophosphorylation and Answers

Biochemistry Multiple Choice Questions on “General Features of Photophosphorylation”.

1. Which of the following statements about thylakoids is false?
A. They contain chlorophyll pigments
B. They contain the photosystems
C. They contain Calvin cycle enzymes
D. They contain the electron transport machinery
Answer: C
Clarification: Chloroplast stroma contains Calvin cycle enzymes and intermediates.

2. Which one of the following is the source of electrons in photosynthesis?
A. Carbohydrates
B. CO₂
C. Water
D. NADH
Answer: C
Clarification: Water is the source of electrons in photosynthesis. These electrons are required to reduce oxidized chlorophyll a molecules.

3. Which of the following about Calvin cycle is correct?
A. It is a metabolic pathway by which plants convert CO₂ into pentose sugars as the main product
B. With decrease in light intensity, the enzymes are more reactive
C. Rubisco adds CO₂ to 3-phosphoglycerate
D. It is a metabolic pathway by which plants convert CO₂ and water into carbohydrates
Answer: D
Clarification: CO₂ combines with ribulose 1, 5-bisphosphate.
The enzymes are more reactive if there is an increase in light intensity.

4. What are the favorable conditions for cyclic photophosphorylation?
A. Aerobic and optimum light
B. Aerobic condition only
C. Aerobic and low light intensity
D. Anaerobic and low light intensity
Answer: A
Clarification: Favorable conditions for cyclic photophosphorylation are aerobic and optimum light.

5. Hydrogen is transferred from the light reaction to the dark reaction in photosynthesis by _____________
A. DPN
B. NAD
C. ATP
D. NADP
Answer: A
Clarification: Diphosphopyridine nucleotide transfers hydrogen from the light reaction to the dark reaction in photosynthesis.

6. Calvin cycle occurs in ____________
A. Cytoplasm
B. Chloroplast
C. Mitochondria
D. Golgi body
Answer: A
Clarification: Calvin cycle occurs in cytoplasm.

7. Light energy is converted to chemical energy in the presence of ____________
A. Chloroplast
B. Ribosomes
C. Mitochondria
D. Stomata
Answer: A
Clarification: Photosynthetic pigment chlorophyll captures the energy from sunlight and converts it and stores it in energy-storage molecules ATP and NADPH.

8. Photosynthesis can be described as ____________
A. Reductive, anabolic, endergonic process
B. Reductive, anabolic, exergonic process
C. Oxidative, anabolic, endergonic process
D. Oxidative, catabolic, exergonic process
Answer: A
Clarification: Photosynthesis involves gaining of electrons; producing complex substances from simpler ones and requires energy.

9. Who is the first person to study the influence of light during photosynthesis?
A. Blackmann
B. Van Niel
C. J. Ingenhouz
D. Warburg
Answer: C
Clarification: Jan Ingenhouz was the best known to show that light is essential for photosynthesis.

10. The percentage of light energy fixed in photosynthesis is around ____________
A. 100%
B. 10%
C. 1%
D. 0.1%
Answer: C
Clarification: Around 1% of light energy is fixed in photosynthesis.

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