Question

The Calvin cycle proceeds in three stages:

1. Reduction, during which carbohydrate is formed at the expense of the photochemically made ATP and NADPH.

2. Regeneration, during which the carbon dioxide acceptor ribulose-1, 5-bisphosphate is formed.

3. Carboxylation, during which carbon dioxide combines with rubulose-1, 5-biphosphate.

Identify the correct sequence.

• A. 3-1-2
• B. 2-1-3
• C. 3-2-1
• D. 1-2-3
• E. 1-3-2

Answer 1

The correct option is A

3-1-2

The Calvin cycle is divided into three phases. The first phase is carboxylation where RuBP is converted to two 3-carbon compounds. The next phase is reduction where ATP and NADPH are used for the synthesis of sugars. The final phase is regeneration where RuBP is regenerated for continuity of the cycle.