During gel electrophoresis , which chemical is used for visualized the fragmented DNA -

Options

A. Ethylene bromide
B. NaBr
C. NaCl
D. Ethidium bromide

Answer

### Step-by-Step Solution:

1. **Understanding Gel Electrophoresis**:
- Gel electrophoresis is a technique used to separate DNA fragments based on their size and mass. Smaller DNA fragments move faster through the gel compared to larger ones.

2. **Identifying the Need for Visualization**:
- After the separation of DNA fragments, it is essential to visualize these fragments to analyze the results.

3. **Exploring Visualization Chemicals**:
- Various chemicals can be used to visualize DNA, but we need to identify which one is specifically used during gel electrophoresis.

4. **Evaluating the Options**:
- The options given are:
- Option 1: Ethylene bromide
- Option 2: Sodium bromide (NADR)
- Option 3: Sodium fluoride (NaCl)
- Option 4: Ethidium bromide

5. **Identifying the Correct Chemical**:
- Ethidium bromide is a fluorescent stain commonly used in gel electrophoresis. When exposed to ultraviolet (UV) light, it emits fluorescence, allowing the DNA fragments to be visualized.

6. **Conclusion**:
- Therefore, the correct answer to the question is **Ethidium bromide** (Option 4).