High School

What is the correct order for the reactions of the Calvin cycle?

A. Carbon fixation, regeneration of RuBP, synthesis of G3P.
B. Synthesis of G3P, regeneration of RuBP, carbon fixation.
C. Carbon fixation, synthesis of G3P, regeneration of RuBP.
D. Regeneration of RuBP, carbon fixation, synthesis of G3P.
E. Synthesis of G3P, carbon fixation, regeneration of RuBP.

Answer :

Final answer:

The correct order for the Calvin cycle is carbon fixation, synthesis of G3P, and regeneration of RuBP. The cycle starts with CO2 combining with RuBP, followed by the production of G3P, and ends with regeneration of RuBP to sustain the cycle. So, the correct option is C. carbon fixation, synthesis of G3P, regeneration of RuBP.

Explanation:

The correct order for the reactions of the Calvin cycle is carbon fixation, synthesis of G3P, and regeneration of RuBP. Specifically, the Calvin cycle involves three main stages:

  1. CO₂ fixation - Carbon dioxide (CO₂) combines with ribulose bisphosphate (RuBP), catalyzed by the enzyme RuBisCO, to produce 3-phosphoglycerate (3-PGA).
  2. Synthesis of G3P - The 3-PGA molecules are then reduced to glyceraldehyde-3-phosphate (G3P), using energy in the form of ATP and reducing power from NADPH.
  3. Regeneration of RuBP - Finally, some of the G3P molecules are used to regenerate RuBP, enabling the cycle to continue.