Number of base pairs of DNA helix in a typical nucleosome

Options

A. 200
B. 100
C. 500
D. 2000

Answer

To determine the number of base pairs of DNA helix in a typical nucleosome, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of a Nucleosome**:
- A nucleosome is a fundamental unit of DNA packaging in eukaryotic cells. It consists of a segment of DNA wrapped around a core of histone proteins.

2. **Identify the Components of a Nucleosome**:
- The nucleosome is made up of a histone octamer, which consists of eight histone proteins. The DNA wraps around this histone octamer.

3. **Determine the Length of DNA Wrapped**:
- In a typical nucleosome, the DNA helix wraps around the histone octamer. The length of DNA that is wrapped around these histones is approximately 200 base pairs.

4. **Select the Correct Answer**:
- Given the options (200, 100, 500, 2000), the correct number of base pairs of DNA helix in a typical nucleosome is **200**.

### Final Answer:
The number of base pairs of DNA helix in a typical nucleosome is **200**.

---