A nucleosome is a portion of the chromonema containing

Options

A. Only histones
B. Both DNA and histones
C. Only DNA
D. Both DNA and RNA

Answer

To solve the question about what a nucleosome contains, we can break it down into the following steps:

### Step 1: Understand the Structure of a Nucleosome
A nucleosome is a fundamental unit of chromatin, which is the material that makes up chromosomes. It consists of DNA wrapped around histone proteins.

### Step 2: Identify the Components of a Nucleosome
The nucleosome is composed of:
- **DNA**: A segment of DNA that is coiled around the histone proteins.
- **Histones**: These are the proteins that help package the DNA into a compact, organized structure. The core of the nucleosome is made up of an octamer of histones, which includes specific types like H2A, H2B, H3, and H4.

### Step 3: Analyze the Options Given
Now, let's look at the options provided in the question:
- **a) Only histones**: This is incorrect because nucleosomes contain DNA as well.
- **b) Both DNA and histones**: This is correct as nucleosomes are made up of both components.
- **c) Only DNA**: This is incorrect because nucleosomes also contain histones.
- **d) Both DNA and RNA**: This is incorrect because nucleosomes do not contain RNA; they only contain DNA and histones.

### Step 4: Conclusion
Based on the analysis, the correct answer is **b) both DNA and histones**.

### Final Answer
**b) Both DNA and histones**

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