Question

Explain why there is twice the amount of glycerate 3-phosphate as ribulose bisphosphate when the carbon dioxide concentration is high. (1)

a) High carbon dioxide levels cause an excess of glycerate 3-phosphate.
b) There is no difference in the amounts of glycerate 3-phosphate and ribulose bisphosphate.
c) High carbon dioxide levels lead to an increased production of ribulose bisphosphate.
d) Ribulose bisphosphate is not affected by carbon dioxide concentrations.

Answer 1

The Calvin cycle involves the enzyme RuBisCO catalyzing the addition of carbon dioxide to ribulose bisphosphate to produce glycerate 3-phosphate. When the carbon dioxide concentration is high, there is twice the amount of glycerate 3-phosphate as ribulose bisphosphate.

Step-by-step explanation:

The Calvin cycle is a series of chemical reactions that occur during photosynthesis. In this cycle, the enzyme ribulose bisphosphate carboxylase (RuBisCO) catalyzes the addition of carbon dioxide to ribulose bisphosphate (RuBP) to form glycerate 3-phosphate (G3P) molecules. Each carbon dioxide molecule that reacts with one RuBP produces two molecules of G3P. Thus, when the carbon dioxide concentration is high, there is twice the amount of G3P as RuBP.