In the process of carbon fixation, RuBP attaches a CO₂ to produce a six-carbon molecule, which is then split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle?
A) addition of a pair of electrons from NADPH
B) inactivation of RuBP carboxylase enzyme
C) regeneration of ATP from ADP
D) regeneration of RuBP
E) regeneration of NADP⁺

Question

Quizplus · Accepted Answer

The regeneration of RuBP is necessary to complete the Calvin cycle, as it is required for the enzyme RuBP carboxylase to attach another CO₂ molecule and begin the process of carbon fixation again. While the other processes mentioned (addition of electrons from NADPH, inactivation of RuBP carboxylase, regeneration of ATP from ADP, and regeneration of NADP⁺) are important in the overall process of photosynthesis, they are not specifically required to complete the Calvin cycle.

In the Process of Carbon Fixation, RuBP Attaches a CO₂