Which is true regarding enzyme nitrite reductase involved in nitrate assimilation?

Options

A. Found in cytoplasm of roots
B. Contain Ni
C. Ruduce `NO_(2)` to `NH_(4)`
D. Reduce `N_(2)`

Answer

### Step-by-Step Solution:

1. **Understanding Nitrate Assimilation**:
- Nitrate assimilation is the process by which plants convert nitrate (NO3-) from the soil into organic forms of nitrogen, primarily ammonium (NH4+), which can be utilized for amino acid and protein synthesis.

2. **Role of Nitrite Reductase**:
- Nitrite reductase is an enzyme that plays a critical role in this process by catalyzing the reduction of nitrite (NO2-) to ammonium (NH4+). This reaction is crucial for the assimilation of nitrogen in plants.

3. **Analyzing the Options**:
- **Option 1**: "Found in cytoplasm of fruits" - This is incorrect. Nitrite reductase is primarily located in chloroplasts, not in the cytoplasm of fruits.
- **Option 2**: "Contains Ni" - This is also incorrect. Nitrite reductase does not contain nickel (Ni) as a cofactor; it typically contains iron (Fe) or other metal ions.
- **Option 3**: "Reduces NO2 to NH4" - This is correct. Nitrite reductase catalyzes the reduction of nitrite to ammonium, which is a key step in nitrate assimilation.
- **Option 4**: "Reduces N2" - This is incorrect. Nitrite reductase does not reduce nitrogen gas (N2); that process is associated with nitrogen-fixing bacteria and other enzymes.

4. **Conclusion**:
- The correct statement regarding the enzyme nitrite reductase involved in nitrate assimilation is that it "reduces NO2 to NH4".

### Final Answer:
The correct option is: **"Reduces NO2 to NH4"**.

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