NEET-UG Biology · Class 11
Calvin cycle and carbon fixation — NEET & JEE Questions
Calvin cycle and carbon fixation is a topic in Photosynthesis in Higher Plants, a Class 11 Biology chapter of the NEET-UG syllabus. TestBudy holds 13 published NEET-UG questions on Calvin cycle and carbon fixation, each with the marking scheme of the real paper.
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Calvin cycle and carbon fixation MCQs with solutions
10 of the 13 published questions on this topic, exactly as they appear in a test. Answers and worked solutions come with your result rather than on this page.
Which five-carbon compound accepts carbon dioxide at the start of the Calvin cycle?
- A. RuBP
- B. PEP, the primary acceptor used in C4 mesophyll cells
- C. OAA
- D. PGA
What is the role of RuBisCO during the carboxylation phase of the Calvin cycle?
- A. It splits water to release oxygen
- B. Carboxylation of RuBP
- C. It transfers electrons from Photosystem I to NADP+
- D. It converts pyruvate directly into glucose
Why must RuBP be regenerated during the Calvin cycle?
- A. It provides oxygen for photorespiration
- B. It is the final carbohydrate exported from the chloroplast
- C. It regenerates the CO2 acceptor RuBP
- D. It acts as the reaction centre of Photosystem I
In the Calvin cycle, carbon dioxide is initially fixed by combining with
- A. RuBP
- B. PEP in every C3 mesophyll cell
- C. glucose
- D. NADPH
Three molecules of carbon dioxide enter the Calvin cycle. How many net molecules of triose phosphate are produced after allowing for RuBP regeneration?
- A. Six
- B. Two
- C. Three
- D. One
How many ATP and NADPH molecules are required to make one molecule of glucose through the Calvin pathway?
- A. 18 ATP and 12 NADPH
- B. 12 ATP and 18 NADPH
- C. 24 ATP and 18 NADPH
- D. 6 ATP and 12 NADPH
How many molecules of ATP and NADPH are required for every molecule of fixed in the Calvin cycle?
- A. 2 molecules of ATP and 3 molecules of NADPH
- B. 2 molecules of ATP and 2 molecules of NADPH
- C. 3 molecules of ATP and 3 molecules of NADPH
- D. 3 molecules of ATP and 2 molecules of NADPH
Which of the following are required for the dark reaction of photosynthesis? A. Light B. Chlorophyll C. D. ATP E. NADPH Choose the correct answer from the options given below:
- A. A, B and C only
- B. B, C and D only
- C. C, D and E only
- D. D and E only
How many ATP and NADPH 2 are required for the synthesis of one molecule of Glucose during Calvin cycle?
- A. 18 ATP and 12 NADPH 2
- B. 12 ATP and 16 NADPH 2
- C. 18 ATP and 16 NADPH 2
- D. 12 ATP and 12 NADPH 2
A chloroplast has abundant ATP but cannot generate NADPH. Which phase of the Calvin cycle would be most directly blocked?
- A. Reduction to triose phosphate
- B. Initial binding of carbon dioxide to RuBP
- C. Formation of oxygen from water
- D. Conversion of PEP to oxaloacetate
Common mistakes in Calvin cycle and carbon fixation
Recorded against questions in this topic that are not shown above, so none of these points at an answer you can see on this page.
- Remembering the 3-CO2 requirement and failing to double it for a six-carbon glucose molecule.
- Counts all formed triose phosphates as net product and ignores RuBP regeneration.
- Assumes the Calvin cycle directly performs the light reactions that generate ATP and NADPH.
Practise this chapter
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