Question

During fixation of one molecule of $C{O}_2$ by $C_3$ plants, number of $ATP$ and $NADP{H}_2$ required are

• A. $3ATP$ and 2$NADP{H}_2$
• B. $5ATP$ and 2$NADP{H}_2$
• C. $12ATP$ and 1 2$NADP{H}_2$
• D. $2ATP$ and 3$NADP{H}_2$

Answer 1

Answer: (A)

$3ATP$ and 2$NADP{H}_2$

For every $C{O}_2$ molecule entering the Calvin cycle, $3$ molecules of $ATP$ and $2$ molecules of NADPH are required. To make one molecule of glucose, $6$ turns of the cycles are required

$(6\times 3ATP=18ATP$ and $6\times 2NADPH=12NADPH)$.

In	Out
$6$ $C{O}_2$	$1glucose$
$18ATP$	$18ADP$
$12NADPH$	$12NADP$, So, the correct answer is '

3ATP and 2NADPH2'