valine amino acids is

Options

A. `alpha`AA
B. `beta`AA
C. `gamma`AA`
D. all the three types

Answer

To determine what type of amino acid valine is, we can follow these steps:

### Step 1: Understand the Structure of Amino Acids
Amino acids consist of a central carbon atom (the alpha carbon) attached to four different groups: an amino group (NH2), a carboxylic acid group (COOH), a hydrogen atom, and a variable side chain (R group).

### Step 2: Identify the Type of Amino Acid
Valine is classified based on the position of the amino group relative to the carboxylic acid group.

- **Alpha Amino Acids**: The amino group is attached to the alpha carbon (the carbon adjacent to the carboxylic acid).
- **Beta Amino Acids**: The amino group is attached to the beta carbon (the second carbon away from the carboxylic acid).
- **Gamma Amino Acids**: The amino group is attached to the gamma carbon (the third carbon away from the carboxylic acid).

### Step 3: Analyze Valine's Structure
In valine, both the carboxylic group (COOH) and the amino group (NH2) are attached to the same carbon atom, which is the alpha carbon. This confirms that valine is an alpha amino acid.

### Step 4: Evaluate the Options
Now, let's evaluate the provided options:
- **A. Alpha amino acid**: Correct, as explained above.
- **B. Beta amino acid**: Incorrect, because valine does not have the amino group on the beta carbon.
- **C. Gamma amino acid**: Incorrect, as the amino group is not on the gamma carbon.
- **D. All three types**: Incorrect, since valine is specifically an alpha amino acid.

### Conclusion
The correct answer is **A. Alpha amino acid**.

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