Ornithine cycle refers to the sequence of biochemical reactions taking place in the

Options

A. liver
B. kidney
C. stomach
D. pancreas

Answer

**Step-by-Step Solution:**

1. **Understanding the Ornithine Cycle**: The ornithine cycle, also known as the urea cycle, is a series of biochemical reactions that convert ammonia, which is toxic, into urea, which is less toxic and can be excreted from the body.

2. **Role of Amino Acids**: The cycle begins with the metabolism of proteins. When proteins are broken down, they yield amino acids. These amino acids contain nitrogen in the form of ammonium ions (NH4+).

3. **Formation of Urea**: The ammonium ions produced from amino acid metabolism combine with carbon dioxide (CO2) to form urea ((NH2)2CO). This reaction is crucial because it helps detoxify ammonia, which is harmful at high concentrations.

4. **Location of the Cycle**: The ornithine cycle occurs in the liver. The liver is the primary organ responsible for detoxifying ammonia and synthesizing urea.

5. **Conclusion**: Therefore, the ornithine cycle refers to the sequence of biochemical reactions taking place in the liver.

**Final Answer**: The ornithine cycle refers to the sequence of biochemical reactions taking place in the **liver**.

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