Which of the following amino acids play important role in ornithine cycle ?

Options

A. Citrubline, glycine
B. Ornithine, citrulline
C. Glycine, methionine
D. Arginine, methionine

Answer

To determine which amino acids play an important role in the ornithine cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Ornithine Cycle**: The ornithine cycle, also known as the urea cycle, is a series of biochemical reactions that occur in the liver. Its primary function is to convert ammonia, which is toxic, into urea for excretion.

2. **Identify the Key Components**: The cycle involves several key components, including the amino acids ornithine and citrulline, as well as enzymes that facilitate the reactions.

3. **Examine the Options**: The options given are:
- A) Citrulline and Glycine
- B) Ornithine and Citrulline
- C) Glycine and Methionine
- D) Arginine and Methionine

4. **Analyze Each Option**:
- **Option A (Citrulline and Glycine)**: While citrulline is involved, glycine is not a key player in the cycle.
- **Option B (Ornithine and Citrulline)**: Both of these amino acids are crucial in the ornithine cycle. Ornithine is a substrate, and citrulline is produced during the cycle.
- **Option C (Glycine and Methionine)**: Neither glycine nor methionine plays a significant role in the ornithine cycle.
- **Option D (Arginine and Methionine)**: Arginine is a product of the cycle but methionine is not involved.

5. **Conclusion**: The amino acids that play an important role in the ornithine cycle are **Ornithine and Citrulline**.

### Final Answer:
The amino acids that play an important role in the ornithine cycle are **Ornithine and Citrulline**.

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