Amino acid that does not contain chiral centre is :

Options

A. Alanine
B. Leucine
C. Valine
D. Glycine

Answer

To determine which amino acid does not contain a chiral center, we first need to understand what a chiral center is. A chiral center, or chiral carbon, is a carbon atom that is bonded to four different atoms or groups.

Let's analyze the given options one by one:

1. **Aniline**: Aniline has the structure where the central carbon is attached to:
- A carboxyl group (COOH)
- An amino group (NH2)
- A hydrogen atom (H)
- A phenyl group (C6H5)

Since the central carbon is attached to four different groups, it is a chiral center.

2. **Leucine**: Leucine has the structure where the central carbon is attached to:
- A carboxyl group (COOH)
- An amino group (NH2)
- A hydrogen atom (H)
- An isobutyl group (C4H9)

Again, the central carbon is bonded to four different groups, making it a chiral center.

3. **Valine**: Valine has the structure where the central carbon is attached to:
- A carboxyl group (COOH)
- An amino group (NH2)
- A hydrogen atom (H)
- An isopropyl group (C3H7)

The central carbon here is also bonded to four different groups, indicating it is a chiral center.

4. **Glycine**: Glycine has the structure where the central carbon is attached to:
- A carboxyl group (COOH)
- An amino group (NH2)
- Two hydrogen atoms (H)

In this case, the central carbon is not bonded to four different groups; it has two hydrogen atoms, which means it does not have a chiral center.

Based on this analysis, the amino acid that does not contain a chiral center is **Glycine**.

**Final Answer**: Glycine (Option D)

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