Which amino acids has phenolic OH group as backbone

Options

A. glycine
B. leucine
C. serine
D. tyrosine

Explanation

To determine which amino acid has a phenolic OH group as part of its structure, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Phenolic OH Group**:
- A phenolic OH group is characterized by a hydroxyl group (-OH) attached to a benzene ring. This structure is important in identifying the correct amino acid.

2. **Identifying Amino Acids**:
- We need to consider the common amino acids and their structures. The amino acids we will focus on are glycine, leucine, serine, and tyrosine.

3. **Analyzing Each Amino Acid**:
- **Glycine**: This amino acid has a simple structure with an amino group (-NH2), a carboxyl group (-COOH), and a hydrogen atom as its side chain. It does not have a phenolic OH group.
- **Leucine**: This is a branched-chain amino acid with an aliphatic side chain. It also lacks a phenolic OH group.
- **Serine**: This amino acid contains a hydroxymethyl group (-CH2OH) in its side chain, but it does not have a phenolic structure.
- **Tyrosine**: This amino acid has a phenolic group in its side chain. Its structure includes an amino group (-NH2), a carboxyl group (-COOH), and a phenolic hydroxyl group (-OH) attached to a benzene ring.

4. **Conclusion**:
- Among the amino acids listed, only **tyrosine** contains a phenolic OH group in its structure.

### Final Answer:
The amino acid that has a phenolic OH group as part of its backbone is **tyrosine**.

---