Which one is component of ornithine cycle

Options

A. Ornithine, citrulline and alanine
B. Ornithine, citrulline and arginine
C. Amino acids are not used
D. Ornithine, citrulline and fumaric acid

Answer

**Step-by-Step Solution:**

1. **Understanding the Ornithine Cycle**: The ornithine cycle, also known as the urea cycle, is a biochemical process that converts ammonia, which is toxic, into urea, a less toxic substance. This process primarily occurs in the liver.

2. **Identifying Components of the Cycle**: The cycle involves several key components. The main substrates and products of the ornithine cycle include:
- **Ornithine**: An amino acid that is a key component of the cycle.
- **Citrulline**: Formed from the reaction of ornithine and carbamoyl phosphate.
- **Arginine**: Produced from citrulline and is converted back into ornithine, completing the cycle.

3. **Evaluating the Options**:
- **Option 1**: Ornithine, citrulline, and alanine - Incorrect because alanine is not part of the ornithine cycle.
- **Option 2**: Ornithine, citrulline, and arginine - Correct as these are the main components of the cycle.
- **Option 3**: Amino acids are not used - Incorrect since ornithine, citrulline, and arginine are amino acids involved in the cycle.
- **Option 4**: Ornithine, citrulline, and fumaric acid - Incorrect because fumaric acid is not a component of the ornithine cycle.

4. **Conclusion**: Based on the analysis, the correct answer is **Option 2: Ornithine, citrulline, and arginine**.

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