Lysine, `H_(2)N-(CH_(2))_(4)-underset(" "NH_(2))underset(|)(CH)-COOH` is...... .
(a)`alpha`-amino acid
(b)`beta`-amino acid
(c)amino acid synthesised in body
(d)None of these

Options

A. `alpha`-amino acid
B. `beta`-amino acid
C. amino acid synthesised in body
D. None of these

Explanation

To determine the correct classification of lysine from the given options, we can analyze its structure and properties step by step.

### Step 1: Understand the Structure of Lysine
Lysine is represented as `H2N-(CH2)4-NH2-CH-COOH`. The structure consists of:
- An amino group (`NH2`)
- A carboxylic acid group (`COOH`)
- A long hydrocarbon chain (four `CH2` groups)

### Step 2: Identify the Type of Amino Acid
Amino acids are classified based on the position of the amino group relative to the carboxylic acid group:
- **Alpha amino acids** have the amino group attached to the carbon that is adjacent to the carboxylic acid carbon (the alpha carbon).
- **Beta amino acids** have the amino group attached to the second carbon (the beta carbon) from the carboxylic acid.

In the case of lysine:
- The amino group is attached to the carbon that is directly next to the carboxylic acid group, making it an alpha amino acid.

### Step 3: Evaluate the Options
Now we can evaluate the provided options:
- (a) **Alpha amino acid**: This is correct as established in Step 2.
- (b) **Beta amino acid**: This is incorrect because lysine does not have its amino group on the beta carbon.
- (c) **Amino acid synthesized in the body**: This is incorrect because lysine is an essential amino acid, meaning it cannot be synthesized by the body and must be obtained from the diet.
- (d) **None of these**: This is incorrect because option (a) is correct.

### Conclusion
The correct answer is (a) **alpha amino acid**.

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