Question

Amount of assimilatory power required to produce 2 molecules of sucrose in a $C_4$ plant is

• A. 30 ATPand 12 NADPH
• B. 60 ATP and 24 NADPH
• C. 36 ATP and 24 NADPH
• D. 120 ATP and 48 NADPH

Answer 1

Answer: (D)

120 ATP and 48 NADPH

As we know that for fixing of 1 CO${}_2$ molecule in C${}_4$ plants: 5ATPs and 2NAPDH molecules are required.

So, for formation of one molecule of sucrose(C${}_1$${}_2$H${}_2$${}_2$O${}_1$${}_1$) which consist of 12 Carbon atoms- 12 CO${}_2$ molecules are needed to be fixed. So, number of ATP and NADPH required are 60 and 24 respectively.

For formation of 2 molecules of sucrose in C${}_4$ plants 60 x 2 ATP and 24 x 2 NADPH will be required.

So, the correct answer is '120 ATP and 48 NADPH'.