Number of ATP required to fix one molecule of nitrogen is

Options

A. 8 ATP
B. 16 ATP
C. 18 ATP
D. 5 ATP

Answer

To determine the number of ATP molecules required to fix one molecule of nitrogen, we can follow these steps:

1. **Understanding Nitrogen Fixation**: Nitrogen fixation is the process by which atmospheric nitrogen (N₂) is converted into ammonia (NH₃) by certain organisms, such as bacteria. Each molecule of nitrogen (N₂) is made up of two nitrogen atoms.

2. **Ammonia Formation**: The fixation of nitrogen results in the formation of two molecules of ammonia (NH₃).

3. **ATP Requirement for Ammonia**: It is known that the fixation of one molecule of ammonia requires 8 ATP molecules.

4. **Calculating Total ATP for Nitrogen Fixation**: Since one molecule of nitrogen produces two molecules of ammonia, we need to calculate the total ATP required for both ammonia molecules:
- ATP required for 1 NH₃ = 8 ATP
- ATP required for 2 NH₃ = 8 ATP × 2 = 16 ATP

5. **Conclusion**: Therefore, to fix one molecule of nitrogen (which produces two molecules of ammonia), a total of 16 ATP molecules are required.

Thus, the number of ATP required to fix one molecule of nitrogen is **16 ATP**.