The peptide linkage formed between glycine `(NH_(2)CH_(2)COOH)` and alanine `underset(CH_(3))underset(|)(NH_(2)CH)-COOH` to give glycylalanine can be shown as

Options

A. `NH_(2)-CH_(2)-NH-underset(CH_(3))underset(|)CH-COOH`
B. `NH_(2)-CH_(2)-CONH-underset(CH_(3))underset(|)CH-COOH`
C. `H_(2)NCOCH_(2)-underset(CH_(3))underset(|)CH-CONH_(2))`
D. `HOOC-CH_(2)-NH-NH-underset(CH_(3))underset(|)CH-COOH`

Explanation

To solve the question regarding the formation of a peptide linkage between glycine and alanine to form glycylalanine, we can follow these steps:

### Step 1: Understand the Structure of Glycine and Alanine
- Glycine (NH₂CH₂COOH) consists of an amino group (NH₂), a hydrogen atom (H), and a carboxylic acid group (COOH).
- Alanine (NH₂CH(CH₃)COOH) consists of an amino group (NH₂), a carbon atom with a methyl group (CH₃), and a carboxylic acid group (COOH).

### Step 2: Identify the Functional Groups
- Both glycine and alanine are alpha-amino acids, which means they contain both an amino group and a carboxylic acid group.
- The carboxylic acid group of glycine will react with the amino group of alanine.

### Step 3: Formation of the Peptide Bond
- A peptide bond is formed when the carboxylic acid group of one amino acid reacts with the amino group of another amino acid.
- This reaction involves the removal of a water molecule (H₂O), which is a condensation reaction.

### Step 4: Write the Reaction
- The reaction can be represented as follows:
- Glycine (NH₂CH₂COOH) + Alanine (NH₂CH(CH₃)COOH) → Glycylalanine (NH₂CH₂CONHCH(CH₃)COOH) + H₂O
- The structure of glycylalanine can be depicted as:
- NH₂CH₂C(=O)NHCH(CH₃)C(=O)OH

### Step 5: Identify the Peptide Linkage
- The peptide bond is the bond formed between the carbon atom of the carboxylic acid group of glycine and the nitrogen atom of the amino group of alanine.
- This bond can be represented as:
- C-NH

### Final Structure of Glycylalanine
- The final structure of glycylalanine can be summarized as:
- NH₂CH₂C(=O)NHCH(CH₃)C(=O)OH

### Conclusion
- The peptide linkage formed between glycine and alanine to give glycylalanine can be shown as:
- NH₂CH₂C(=O)NHCH(CH₃)C(=O)OH