Nitrogenase enzyme does not require for its activity

Options

A. 16 ATP
B. Leghaemoglobin
C. Rhizobia
D. `NADH_(2)`

Answer

To solve the question "Nitrogenase enzyme does not require for its activity," we need to analyze the options provided and understand the function of the nitrogenase enzyme in nitrogen fixation.

### Step-by-Step Solution:

1. **Understanding Nitrogenase Enzyme**:
- Nitrogenase is an enzyme that catalyzes the conversion of atmospheric nitrogen (N₂) into ammonia (NH₃), a process known as nitrogen fixation. This is crucial for plants as they cannot directly utilize atmospheric nitrogen.

2. **Identifying Requirements for Nitrogenase Activity**:
- The activity of nitrogenase requires several components:
- **ATP**: 16 ATP molecules are required to fix two molecules of ammonia, which means 8 ATP are needed for one ammonia molecule.
- **Leghemoglobin**: This component is important as it helps maintain an anaerobic environment, protecting nitrogenase from oxygen, which can inhibit its activity.
- **Rhizobia**: These are symbiotic bacteria that contain nitrogenase and are essential for the nitrogen fixation process in legumes.
- **NADH₂**: This is involved in providing reducing power for the nitrogen fixation process.

3. **Analyzing the Options**:
- The question asks which component is **not required** for the activity of nitrogenase.
- **16 ATP**: Required for the enzymatic reaction.
- **Leghemoglobin**: Required to protect nitrogenase from oxygen.
- **Rhizobia**: Required as they house the nitrogenase enzyme.
- **NADH₂**: While it can be involved in the process, nitrogenase itself does not directly require NADH₂ for its activity.

4. **Conclusion**:
- The correct answer is **NADH₂**, as nitrogenase does not require it directly for its activity.

### Final Answer:
**NADH₂** is not required for the activity of nitrogenase enzyme.