Question

Fixation of one $C{O}_2$ molecule through Calvin cycle requires

• A. $1$ ATP and $2NADP{H}_2$
• B. $2$ ATP and $2NADP{H}_2$
• C. $3$ ATP and $2NAD{H}_2$
• D. $2$ ATP and $1NADP{H}_2$

Answer 1

The correct option is C $3$ ATP and $2NAD{H}_2$

The Calvin cycle has three stages.

1)carbon fixation

2)reduction

3)regeneration.

At the end of each Calvin cycle net gain is 9ATP and 6 NADPH2.In each Calvin cycle, 3 CO2 molecules are fixed with RuBP to form 2 molecules of 3PGA in the first step. Later two molecules of 3PGA through a series of reactions regenerate 2RuBP in the third stage. So, for the fixation of one CO2 carbon dioxide molecule through the Calvin cycle requires 3ATP and 2NADPH2.

So, the correct answer is 'option C'.