The amino acid ,Arginine, is rich in

Options

A. `H_(2A) , H_(2B)`
B. `H_3, H_4`
C. `H_1 `
D. `H_1 , H_(2A)`

Answer

To determine what the amino acid arginine is rich in, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Nature of Arginine**:
- Arginine is classified as an amino acid. It is one of the 20 standard amino acids used by cells to synthesize proteins.

2. **Identify the Role of Arginine**:
- Arginine is known for its basic properties. It has a positively charged side chain at physiological pH, which makes it a basic amino acid.

3. **Connect Arginine to Histones**:
- In the context of proteins, arginine is particularly abundant in histones. Histones are proteins that help package DNA into a compact, organized structure in the nucleus of eukaryotic cells.

4. **Identify Specific Histones Rich in Arginine**:
- Among the different types of histones (H2A, H2B, H3, H4, H1), histones H3 and H4 are specifically known to be rich in arginine. These histones play a crucial role in the structure of chromatin and gene regulation.

5. **Evaluate the Options**:
- Given the options provided (H2A, H2B, H3, H4, H1), we can conclude that histones H3 and H4 are the correct answers as they are known to be rich in arginine.

6. **Final Conclusion**:
- Therefore, the amino acid arginine is rich in histones H3 and H4.

### Final Answer:
Arginine is rich in histones H3 and H4.