Which of the group in amino acids makes them unique -

Options

A. R group
B. `NH_(2)` group
C. COOH group
D. None

Answer

To determine which group in amino acids makes them unique, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Amino Acids**:
- Amino acids have a basic structure that includes four key components: an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (H), and a variable side chain known as the R group.

2. **Identify Common Components**:
- The amino group and the carboxyl group are common to all amino acids. This means that these parts do not contribute to the uniqueness of each amino acid.

3. **Focus on the R Group**:
- The R group (or side chain) is the variable part of the amino acid structure. It differs from one amino acid to another, which is what gives each amino acid its unique properties.

4. **Examples of R Groups**:
- For instance, if the R group is CH3, the amino acid is alanine. If the R group is H, the amino acid is glycine. If the R group is CH2OH, the amino acid is serine. Each of these variations in the R group leads to different amino acids with distinct characteristics.

5. **Conclusion**:
- Therefore, the group in amino acids that makes them unique is the R group. This is the only part that varies among different amino acids, while the amino and carboxyl groups remain constant.

### Final Answer:
The R group in amino acids makes them unique.

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