The net electric charge on DNA and histones is

Options

A. both positive
B. both negative
C. negative and positive, respectively
D. zero

Answer

To determine the net electric charge on DNA and histones, we can break down the information step by step:

### Step 1: Understanding the Charges of DNA and Histones
- DNA is known to have a **negative charge**. This is primarily due to the phosphate groups in its backbone, which carry a negative charge.
- Histones, on the other hand, are proteins that are rich in basic amino acids such as lysine and arginine. These amino acids have side chains that carry a **positive charge**.

### Step 2: The Interaction between DNA and Histones
- In eukaryotic cells, DNA is organized into a structure called chromatin. Within this structure, DNA wraps around histone proteins to form nucleosomes.
- The negatively charged DNA wraps around the positively charged histone octamer (which consists of eight histone molecules). This interaction helps in the compact organization of DNA within the nucleus.

### Step 3: Conclusion on the Net Electric Charge
- Since DNA is negatively charged and histones are positively charged, the net electric charge can be described as:
- **DNA: Negative charge**
- **Histones: Positive charge**
- Therefore, the overall charge when considering both components is **negative for DNA and positive for histones**.

### Final Answer
- The net electric charge on DNA and histones is **negative and positive respectively** (Option C).

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