During the Calvin Cycle, which molecules accompany the reduction of 3-PG to G3P?

During the Calvin Cycle, which molecules accompany the reduction of 3-PG to G3P?

• A. ATP and NADH
• B. NADPH
• C. ATP only
• D. NADH only

Answer: (A)

The reduction of 3-PG to G3P is driven by NADPH, which donates the electrons needed to convert 3-PG into G3P. In the Calvin cycle, 3-PG is first phosphorylated by ATP to form 1,3-bisphosphoglycerate, and then NADPH reduces that intermediate to G3P. So the molecule accompanying the reduction step is NADPH; ATP provides energy in the preceding phosphorylation but is not the reducing agent in the actual reduction step. Note that NADPH, not NADH, is used in the chloroplasts for this pathway.

The reduction of 3-PG to G3P is driven by NADPH, which donates the electrons needed to convert 3-PG into G3P. In the Calvin cycle, 3-PG is first phosphorylated by ATP to form 1,3-bisphosphoglycerate, and then NADPH reduces that intermediate to G3P. So the molecule accompanying the reduction step is NADPH; ATP provides energy in the preceding phosphorylation but is not the reducing agent in the actual reduction step. Note that NADPH, not NADH, is used in the chloroplasts for this pathway.