Which is not true for nitrogenase enzyme in root nodules in legumes?

Options

A. Synthesized by nit genes of Rhizobium
B. Site of reduction of `N_(2) " into " NH_(3)`
C. It is a Mo-Fe protein
D. Resistant to `O_(2)` concentration

Answer

To determine which statement is not true for the nitrogenase enzyme in root nodules of legumes, we will analyze each option provided in the question.

### 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 essential for nitrogen fixation in legumes.

2. **Analyzing the Options**:
- **Option A**: "The nitrogenase enzyme is synthesized by the nitrogen of the rhizobium."
- This statement is misleading. The nitrogenase enzyme is synthesized by the rhizobium bacteria, specifically through the expression of NIF genes, not by nitrogen itself. This makes Option A potentially incorrect.

- **Option B**: "It is a site of the reduction of N2 into NH3."
- This statement is true. The primary function of nitrogenase is to reduce atmospheric nitrogen (N2) to ammonia (NH3).

- **Option C**: "The nitrogenase enzyme has two components: a metal iron protein and a molybdenum iron protein."
- This statement is also true. Nitrogenase consists of two components: a dinitrogenase (which contains molybdenum) and a dinitrogenase reductase (which contains iron).

- **Option D**: "This enzyme is resistant to O2 concentration."
- This statement is false. Nitrogenase is sensitive to oxygen and cannot function in the presence of high oxygen concentrations. It often operates in anaerobic conditions to avoid oxygen.

3. **Conclusion**:
- After analyzing all the options, we find that Option A is misleading and not true, while Options B, C, and D contain accurate information about the nitrogenase enzyme.

### Final Answer:
The statement that is not true for nitrogenase enzyme in root nodules in legumes is **Option A**.

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