Back to your test review

In the reduction stage of the Calvin cycle, the energy carriers used per CO2 fixed are

  • (a) 1 ATP and 1 NADPH Your answer
  • (b) 2 ATP and 2 NADPH Correct
  • (c) 2 ATP and 3 NADPH Your answer
  • (d) 3 ATP and 2 NADPH Your answer
Your answer: Correct answer: (b)
Advertisement

Explanation

Why (b) is correct

In the reduction stage, 2 ATP and 2 NADPH are used for each CO2 fixed, to reduce PGA to triose phosphate. The third ATP is used in regeneration.

Why the other options are wrong

  • (a) · your answer Reduction needs two of each, not one.
  • (c) · your answer Only 2 NADPH are used.
  • (d) · your answer 3 ATP and 2 NADPH is the total per CO2, not for the reduction stage alone.
NCERT point: Reduction: 2 ATP + 2 NADPH per CO2; regeneration: 1 ATP per CO2.
What is wrong?
Thank you! We will check this question.
Practise Photosynthesis in Higher Plants
Take a free 15-question NEET Biology test on this chapter. Timed, scored instantly.
Start free test

Similar questions

The regeneration of RuBP requires, per CO2 fixed, In the reduction phase of the Calvin cycle, ATP is used for How many molecules of CO2 must be fixed to produce one molecule of glucose?