Question

How many ATP and $NADP{H}_2$ are required for the fixation of 3 molecules of $C{O}_2$ in Calvin cycle?

• A. 9 ATP and 6 $NADP{H}_2$
• B. 8 ATP and 6 $NADP{H}_2$
• C. 9 ATP and 3 $NADP{H}_2$
• D. 6 ATP and 9 $NADP{H}_2$

Answer 1

Answer: (A)

9 ATP and 6 $NADP{H}_2$

The cycle spends ATP as an energy source and consumes $NADP{H}_2$ as reducing power for adding high energy electrons to make the sugar, which are end products of light reactions. For fixation of 1 $C{O}_2$, 3 ATP molecules and 2 $NADP{H}_2$ are required. Thus, for fixation of 3 $C{O}_2$, 9ATP and 6$NADP{H}_2$ will be required.

So, the correct answer is '9 ATP and 6$NADP{H}_2$