The ratio between Histone .2. and Histone 1 associated with eukaryotic DNA, respectively?

Options

A. `2:1`
B. 1: 2`
C. `1: 4`
D. `4:1 `

Answer

To solve the question regarding the ratio between Histone 2 and Histone 1 associated with eukaryotic DNA, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nucleosomes**:
- Nucleosomes are the basic units of DNA packaging in eukaryotic cells. Each nucleosome consists of a segment of DNA wrapped around a core of histone proteins.

2. **Identifying Histones in the Nucleosome**:
- The core of the nucleosome is made up of a histone octamer, which includes two copies each of four different histones: H2A, H2B, H3, and H4. Therefore, we have:
- 2 H2A
- 2 H2B
- 2 H3
- 2 H4

3. **Counting Histone 2**:
- Histone 2 refers to both H2A and H2B. Since there are 2 of each, we can calculate:
- Total Histone 2 = 2 (H2A) + 2 (H2B) = 4

4. **Counting Histone 1**:
- Histone 1 (H1) is not part of the octamer but is associated with the nucleosome. Typically, there is one H1 associated with each nucleosome.
- Therefore, for each nucleosome, we have:
- Total Histone 1 = 1

5. **Calculating the Ratio**:
- Now, we can establish the ratio of Histone 2 to Histone 1:
- Ratio = Histone 2 : Histone 1 = 4 : 1

6. **Conclusion**:
- The correct answer to the question is that the ratio between Histone 2 and Histone 1 associated with eukaryotic DNA is **4:1**.