Histone octamer acts as the core of the nucleosome. The type of histone which is not a component of octamer?

Options

A. `H_2A`
B. `H_2B`
C. `H_4`
D. `H_1 `

Answer

To answer the question regarding which histone is not a component of the histone octamer, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Nucleosome**:
- The nucleosome is the fundamental unit of chromatin, consisting of a segment of DNA wrapped around a core of histone proteins.

2. **Identify the Components of the Histone Octamer**:
- The histone octamer is composed of eight histone proteins. Specifically, it includes:
- 2 molecules of H2A
- 2 molecules of H2B
- 2 molecules of H3
- 2 molecules of H4

3. **Recognize the Role of H1**:
- H1 is a linker histone, which means it binds to the DNA between nucleosomes and helps in the compaction of chromatin. It does not form part of the core octamer.

4. **Conclusion**:
- Since H1 is not part of the histone octamer and does not contribute to the core of the nucleosome, it is the correct answer to the question.

### Final Answer:
The type of histone which is not a component of the octamer is **H1**.