Deamination is the first step in urea formation. It means the

Options

A. Reduction of ammonia
B. Oxidation of ammonia
C. Addition of amino group to a non-amino organic molecule
D. Removal of amino group from an amino acid

Answer

**Step-by-Step Solution:**

1. **Understanding Deamination**: Deamination is the biochemical process where an amino group (-NH2) is removed from an amino acid. This is essential for the metabolism of proteins and occurs primarily in the liver and kidneys.

2. **Role of Enzymes**: The process of deamination is facilitated by enzymes known as deaminases. These enzymes catalyze the removal of the amino group from the amino acid.

3. **Occurrence of Deamination**: Deamination typically occurs when there is an excess intake of proteins in the diet. The body needs to process these excess proteins, and deamination is the first step in this process.

4. **Formation of Ammonia**: During deamination, the amino group is converted into ammonia (NH3). This ammonia is toxic to the body and must be converted into a less harmful substance.

5. **Connection to Urea Cycle**: The ammonia produced from deamination enters the urea cycle, where it is converted into urea, a less toxic compound that can be safely excreted from the body through urine.

6. **Final Definition**: Therefore, deamination can be defined as the removal of the amino group from an amino acid, which is the first step in the formation of urea.

**Final Answer**: Deamination is the first step in urea formation; it means the removal of the amino group from an amino acid.

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