The correct structure of the dipeptide gly-ala is

Options

A.
B.
C.
D.

Explanation

To determine the correct structure of the dipeptide Gly-Ala (glycine-alanine), we can follow these steps:

### Step 1: Identify the Amino Acids
The two amino acids involved in forming the dipeptide are glycine and alanine.

- **Glycine (Gly)**: Its structure is represented as:
- NH2 (amino group)
- CH2 (carbon)
- COOH (carboxylic acid group)

- **Alanine (Ala)**: Its structure is represented as:
- NH2 (amino group)
- CH (carbon)
- CH3 (methyl group)
- COOH (carboxylic acid group)

### Step 2: Determine N-terminal and C-terminal
In a dipeptide, the N-terminal is the end of the molecule with a free amino group (NH2), and the C-terminal is the end with a free carboxylic acid group (COOH).

- **N-terminal**: Glycine (NH2 group)
- **C-terminal**: Alanine (COOH group)

### Step 3: Form the Peptide Bond
When glycine and alanine combine to form the dipeptide Gly-Ala, a peptide bond is formed through a condensation reaction, which involves the elimination of a water molecule (H2O).

The reaction can be represented as:
- Glycine (NH2-CH2-COOH) + Alanine (NH2-CH(CH3)-COOH) → Gly-Ala (NH2-CH2-CO-NH-CH(CH3)-COOH) + H2O

### Step 4: Draw the Structure
The structure of the dipeptide Gly-Ala can be depicted as follows:
- Start with the N-terminal glycine: NH2-CH2-CO
- Connect it to the C-terminal alanine: -NH-CH(CH3)-COOH

The complete structure is:
```
NH2
|
CH2
|
C=O
|
NH
|
CH
|
CH3
|
C=O
|
OH
```

### Step 5: Verify the Structure
Ensure that the structure reflects the correct order of amino acids: glycine at the N-terminal and alanine at the C-terminal.

### Final Structure
The correct structure of the dipeptide Gly-Ala is:
- Glycine (N-terminal) linked to Alanine (C-terminal) through a peptide bond.