Question

In C${}_3$ plants, to produce three glucose molecules .......... ATP and ........... NADPH${}_2$ molecules are required.

• A. 54, 36
• B. 64, 30
• C. 36, 60
• D. 18, 12

Answer 1

The correct option is A 54, 36

The net reaction of Calvin cycle is :

6RuBP + 6CO₂ + 18ATP + 12NADPH -----> 6RuBP + C₆H₁₂O₆ + 18ADP + 12NADPH⁺ + 18Pi

One molecule of CO₂ is fixed in one C3 cycle. Thus, 6 turns of cycle are required to fix 6 molecules of CO₂ i.e. to form glucose (C₆H₁₂O₆).

For 1 molecule of glucose ATP required are 18 and NADPH required are 12

So, for 3 molecule of glucose, ATP required are equal to 3 x 18 = 54 and NADPH required are equal to 12 x 3 = 36

So, the correct answer is '54, 36'.