In `C_4` plants , numbers of ATP and NADPH molecules required to fiz 2 molecules of `CO_2` are respectively

Options

A. 6 & 10
B. 10 & 6
C. 4 & 10
D. 10 & 4

Answer

To solve the question regarding the number of ATP and NADPH molecules required to fix 2 molecules of CO2 in C4 plants, we can follow these steps:

### Step 1: Understand the C4 Cycle
C4 plants utilize a specific pathway known as the C4 cycle for carbon fixation. In this cycle, CO2 is initially fixed into a 4-carbon compound.

### Step 2: Determine the Requirements for One Molecule of CO2
From the C4 cycle, we know that:
- To fix one molecule of CO2, 5 ATP molecules are required.
- To fix one molecule of CO2, 3 NADPH molecules are required.

### Step 3: Calculate for Two Molecules of CO2
Since the question asks for the requirements to fix 2 molecules of CO2, we need to multiply the requirements for one molecule by 2:
- ATP required for 2 CO2 = 5 ATP × 2 = 10 ATP
- NADPH required for 2 CO2 = 3 NADPH × 2 = 6 NADPH

### Step 4: Final Answer
Thus, the total number of ATP and NADPH molecules required to fix 2 molecules of CO2 in C4 plants are:
- ATP: 10
- NADPH: 6

### Conclusion
The answer is 10 ATP and 6 NADPH.