For formation of urea which one of the following is required along with ammonia

Options

A. (a) Arginase, `CO_(2)` and `O_(2)`
B. (b) Arginase, `CO_(2)` and water
C. (c) Aspartate, `CO_(2)` and water
D. (d) Aspartate, `CO_(2)` and `O_(2)`

Answer

To answer the question regarding the formation of urea and what is required along with ammonia, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Urea Cycle**:
- The urea cycle, also known as the ornithine cycle, is the process through which urea is formed in the liver from excess amino acids.

2. **Deamination Process**:
- The first step in the urea cycle involves the deamination of amino acids, which occurs in the liver. During this process, the amino group (NH2) is removed from amino acids, resulting in the formation of ammonia (NH3).

3. **Formation of Ammonium Ions**:
- The ammonia produced is converted into ammonium ions (NH4+) in the liver, which is a less toxic form of ammonia.

4. **Condensation with Bicarbonate**:
- The urea cycle begins with the condensation of ammonium ions with bicarbonate ions (HCO3-). This reaction is catalyzed by the enzyme carbamoyl phosphate synthase, leading to the formation of carbamoyl phosphate.

5. **Formation of Citrulline**:
- Carbamoyl phosphate then combines with ornithine to form citrulline, facilitated by the enzyme ornithine transcarbamylase.

6. **Combining with Aspartate**:
- Citrulline is then transported to the cytosol, where it combines with aspartate (another amino acid) to form argininosuccinate, catalyzed by the enzyme argininosuccinate synthetase.

7. **Cleavage to Arginine and Fumarate**:
- Argininosuccinate is then cleaved into arginine and fumarate by the enzyme argininosuccinate lyase.

8. **Final Steps**:
- Finally, arginine is converted back to ornithine and urea by the enzyme arginase, completing the cycle. This step also releases urea, which is excreted from the body.

9. **Conclusion**:
- Therefore, along with ammonia, the key components required for the formation of urea include bicarbonate ions (HCO3-), ornithine, and the enzyme arginase. The correct answer to the question is that bicarbonate ions are required along with ammonia for the formation of urea.

### Final Answer:
Bicarbonate ions (HCO3-) are required along with ammonia for the formation of urea.