Question: 117 How many ATP and \mathrm{NADPH}_{2} are required for the synthesis of one molecule of Glucose during Calvin cycle?
(1) 12 ATP and 16 \mathrm{NADPH}_{2}
(2) 18 ATP and 16 \mathrm{NADPH}_{2}
(3) 12 ATP and 12 \mathrm{NADPH}_{2}
(4) 18 ATP and 12 \mathrm{NADPH}_{2}
Answer: Option (4)
Explanation:
The Calvin cycle synthesizes one molecule of glucose from six molecules of carbon dioxide.
For fixation of one molecule of \mathrm{CO}_{2},
the Calvin cycle requires 3 ATP and 2 molecules of
\mathrm{NADPH}_{2}.
Since one molecule of glucose is formed from six molecules of \mathrm{CO}_{2},
the total energy requirement becomes:
ATP required = 6 \times 3 = 18
\mathrm{NADPH}_{2} required = 6 \times 2 = 12
Thus, synthesis of one molecule of glucose during the Calvin cycle requires 18 ATP and 12 molecules of \mathrm{NADPH}_{2}.
Hence, Option (4) is the correct answer.