C3 Cycle

Q. The most crucial step of Calvin cycle is:

1. Oxidation
2. Reduction
3. Regeneration
4. Carboxylation

Q. During dark reaction for fixation of carbon, the three carbon atoms of each molecule of 3 phosphoglyceric acid (PGA) are derived from

1. CO₂ Only
2. RuBP only
3. RuBP +CO₂ +PEP
4. RuBP +CO₂

Q. Which enzyme fixes CO₂ in Calvin cycle?

1. Carbonic anhydrase
2. Hexokinase
3. RUBP carboxylase
4. PEP carboxylase

Q.

How many carbon atoms are in a molecule of RuBP?

1. one

2. two

3. five

4. three

Q.

Which of the following does not occur during the Calvin cycle?

1. carbon fixation

2. oxidation of NADPH

3. release of oxygen

4. regeneration of the CO2 acceptor

Q.

What is the primary function of the Calvin cycle?

1. use NADPH to release carbon dioxide

2. split water and release oxygen

3. synthesize simple sugars from carbon dioxide

4. use ATP to release carbon dioxide

Q.

To reduce six molecules of carbon dioxide to glucose via photosynthesis, how many molecules of NADPH and ATP are required?

1. 6 NADPH and 6 ATP

2. 12 NADPH and 18 ATP

3. 18 NADPH and 12 ATP

4. 12 NADPH and 12 ATP

Q. During photosynthesis,

1. Oxygen evolved comes from CO₂
2. ATP is formed
3. ATP is not formed
4. Water is required as medium but it does not take part in photosynthesis.

Q. Ribulose-1, 5-bisphosphate carboxylase/oxygenase enzyme catalyses the carboxylation between

1. Ribulose-1, 5-bisphosphate and carbon dioxide

2. Ribulose-5-phosphate and oxygen

3. 3-Phospho glyceraldehyde and dihydroxyacetone phosphate

4. Oxaloacetic acid and Acetyl CoA

Q. The sugar produced in the reduction phase of the Calvin cycle is 3-PGA.

1. True

2. False