Question

For a plant to synthesize 3 molecules of G-3-P, the Calvin cycle uses __ molecules of CO2, __ molecules of ATP, and __ molecules of NADPH?

Answer 1

Answer: During Calvin cycle, carbon dioxide is fixed by RUBISCO to produce glucose. First, carbon dioxide is fixed to three carbon compound called as glyceraldehyde-3-phosphate that is later used to synthesize glucose and regeneration of  ribulose-1,5-bisphosphate. For each molecule of G-3-P formation 0.5 molecules of CO2, 1 ATP and 1 NADPH are required. So, to synthesize three molecules of G-3-P, 1.5 molecules of CO2, 3 ATP and 3 NADPH are required.