Question

how many G3P molecules is needed for the formation of 1 glucose molecule in the calvin cycle? A. 4 B. 3 C. 2 or D. 1

Answer 1

The calvin cycle is the process of carbon fixation by plants which means that plants captures carbon di-oxide, water and sunlight and convert them into glucose molecule. The site of calvin cycle is stroma (chloroplast) in green leaves.

Just before calvin cycle, light reaction occurs in grana of green leaves, which produces ATP and NADPH. The calvin cycle (C3) cycle uses this ATP and NADPH to convert carbon di oxide into glucose molecule. The calvin cycle involves three processes:

1. Carbon fixation: fixes carbon di oxide and produces 3-phosphoglycerate

2. Reduction: using ATP and NADPH, 3-phosphoglycerate is converted into glyceraldehyde 3 phosphate (6 molecules)

3. Regeneration of RuBP (Rubsico) Enzyme: one molecule of glyceraldehyde 3 phosphate leaves the cycle as glucose, and the remaining five molecules of glyceraldehyde 3 phosphate are used to synthesize RuBP enzyme.

So, the answer is D-1 molecule of glyceraldehyde 3 phosphate.