Statement-1 : Gly-Ala is a structural isomer pf Ala-Gly.
Statement-2 : In Al-Gly, Alanine is the `N`-terminal amino acid.

Options

A. STATEMENT-1 is true, STATEMENT-2 is true and STATEMENT-2 is
correct explanation for STATEMENT-1
B. STATEMENT-1 is true, STATEMENT-2 is true and STATEMENT-2 is not correct explanation for STATEMENT-1
C. STATEMENT-1 is true, STATEMENT-2 is false
D. STATEMENT-1 is false, STATEMENT-2 is true

Explanation

To analyze the statements provided in the question, we will break down the reasoning step by step.

### Step 1: Understanding the Statements
- **Statement 1**: Gly-Ala is a structural isomer of Ala-Gly.
- **Statement 2**: In Ala-Gly, Alanine is the N-terminal amino acid.

### Step 2: Identifying the Amino Acids
- Glycine (Gly) has the structure: H2N-CH2-COOH
- Alanine (Ala) has the structure: H2N-CH(CH3)-COOH

### Step 3: Formation of Peptides
- **Gly-Ala**: When glycine and alanine are combined, the peptide bond forms between the amino group of glycine and the carboxyl group of alanine, resulting in:
- Structure: H2N-CH2-CO-NH-CH(CH3)-COOH
- Here, glycine is at the N-terminal and alanine is at the C-terminal.

- **Ala-Gly**: When alanine and glycine are combined, the peptide bond forms between the amino group of alanine and the carboxyl group of glycine, resulting in:
- Structure: H2N-CH(CH3)-CO-NH-CH2-COOH
- Here, alanine is at the N-terminal and glycine is at the C-terminal.

### Step 4: Identifying N-terminal and C-terminal
- **N-terminal**: The amino acid with a free amino group (NH2) at one end of the peptide.
- **C-terminal**: The amino acid with a free carboxyl group (COOH) at the other end of the peptide.

In **Ala-Gly**, alanine is indeed the N-terminal amino acid, confirming Statement 2 is correct.

### Step 5: Checking for Structural Isomerism
- Structural isomers have the same molecular formula but different structures.
- Both Gly-Ala and Ala-Gly have the same molecular formula:
- Total Carbons (C): 5
- Total Hydrogens (H): 10
- Total Nitrogens (N): 2

Since they differ in structure (the order of amino acids is different), they are indeed structural isomers, confirming Statement 1 is also correct.

### Conclusion
- **Statement 1**: True (Gly-Ala is a structural isomer of Ala-Gly)
- **Statement 2**: True (In Ala-Gly, alanine is the N-terminal amino acid)
- However, Statement 2 does not explain Statement 1.

### Final Answer
- Statement 1 is true.
- Statement 2 is true.
- Statement 2 is not the correct explanation for Statement 1.