Based on the nature of R group there are many amino acids. If the R group in a proteinaceous amino acid is a methyl group, then the amino acids is

Options

A. Glycine
B. Alanine
C. Serine
D. Phenylalanine

Answer

To solve the question regarding which amino acid has a methyl group as its R group, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Amino Acids**:
- Amino acids are the building blocks of proteins. Each amino acid has a central carbon atom (alpha carbon) to which four different groups are attached: an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (H), and a variable R group (side chain).

2. **Identifying the R Group**:
- The R group (side chain) is what differentiates one amino acid from another. The nature of this R group determines the characteristics and classification of the amino acid.

3. **Recognizing the Methyl Group**:
- A methyl group is represented as -CH3. We need to identify which amino acid has this specific structure in its R group.

4. **Listing Common Amino Acids**:
- There are 20 standard amino acids. Among them, we can analyze the structure of each to find the one with a methyl group as its R group.

5. **Identifying Alanine**:
- Upon reviewing the amino acids, we find that alanine is the amino acid that has a methyl group (-CH3) as its R group. Its structure can be summarized as follows:
- Amino group: -NH2
- Carboxyl group: -COOH
- R group: -CH3 (methyl group)

6. **Conclusion**:
- Therefore, the amino acid with a methyl group as its R group is **alanine**.

### Final Answer:
The amino acid with a methyl group as its R group is **alanine**.

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