Nitrosomonas and Nitrococcus oxidise

Options

A. Nitrate to nitrogen
B. `CO_2` to carbohydrates
C. `N_2" to "NO_3`
D. `NH_3` to nitrite

Answer

**Step-by-Step Solution:**

1. **Identify the Bacteria**: The question mentions two specific bacteria: Nitrosomonas and Nitrococcus. Both of these are known as nitrifying bacteria.

2. **Understand Nitrification**: Nitrification is a biological process where ammonia is converted into nitrite and then into nitrate. This process is crucial for the nitrogen cycle, as it makes nitrogen available to plants in a form they can absorb.

3. **Determine the Function of Nitrosomonas and Nitrococcus**:
- Nitrosomonas specifically oxidizes ammonia (NH3) into nitrite (NO2-).
- Nitrococcus also plays a role in the nitrification process, often converting nitrite into nitrate (NO3-).

4. **Analyze the Options Given**:
- **Nitrate to nitrogen**: This is incorrect; nitrifying bacteria do not convert nitrate back to nitrogen gas.
- **Carbon dioxide to carbohydrates**: This is incorrect; nitrifying bacteria do not perform photosynthesis.
- **Nitrogen to nitrate**: This is incorrect; they do not directly convert atmospheric nitrogen to nitrate.
- **Ammonia to nitrite**: This is correct; both Nitrosomonas and Nitrococcus oxidize ammonia to nitrite.

5. **Conclusion**: The correct answer is that Nitrosomonas and Nitrococcus oxidize ammonia to nitrite.

**Final Answer**: Ammonia to nitrite.

---