A tripeptide is written as Glycine-Alanine-Glycine. The correct
structure of tripeptide.

Options

A.
B.
C.
D. All of these

Answer

To determine the correct structure of the tripeptide Glycine-Alanine-Glycine, we will follow these steps:

### Step 1: Identify the Structures of the Amino Acids
- **Glycine (Gly)**: The structure of glycine is represented as:
\[ \text{H}_2\text{N}-\text{CH}_2-\text{COOH} \]
- **Alanine (Ala)**: The structure of alanine is represented as:
\[ \text{H}_2\text{N}-\text{CH}(\text{CH}_3)-\text{COOH} \]

### Step 2: Combine the Amino Acids to Form the Tripeptide
The tripeptide Glycine-Alanine-Glycine consists of two glycine molecules and one alanine molecule. The sequence is:
1. Glycine (Gly)
2. Alanine (Ala)
3. Glycine (Gly)

### Step 3: Form Peptide Bonds
Peptide bonds are formed by the condensation reaction between the amino group of one amino acid and the carboxyl group of another, releasing a water molecule (H2O).

- **First Peptide Bond**: Between the first Glycine and Alanine.
- **Second Peptide Bond**: Between Alanine and the second Glycine.

### Step 4: Write the Structure of the Tripeptide
1. Start with the first Glycine:
\[ \text{H}_2\text{N}-\text{CH}_2-\text{COOH} \]
2. Connect it to Alanine:
\[ \text{H}_2\text{N}-\text{CH}_2-\text{C(=O)}-\text{NH}-\text{CH}(\text{CH}_3)-\text{COOH} \]
3. Connect Alanine to the second Glycine:
\[ \text{H}_2\text{N}-\text{CH}_2-\text{C(=O)}-\text{NH}-\text{CH}(\text{CH}_3)-\text{C(=O)}-\text{NH}-\text{CH}_2-\text{COOH} \]

### Final Structure of the Tripeptide
The final structure can be summarized as:
\[ \text{H}_2\text{N}-\text{CH}_2-\text{C(=O)}-\text{NH}-\text{CH}(\text{CH}_3)-\text{C(=O)}-\text{NH}-\text{CH}_2-\text{COOH} \]