In agarose gel electrophoresis–

Options

A. DNA migrates towards negative electrode
B. Larger molecules migrate faster than smaller molecules
C. Ethidium bromide can be used to visualize the DNA fragments
D. Pink coloured bands of DNA can be visualized when gel exposed to UV light

Answer

### Step-by-Step Solution:

1. **Understanding Agarose Gel Electrophoresis**: Agarose gel electrophoresis is a technique used to separate DNA fragments based on their size and charge. DNA is negatively charged due to its phosphate backbone.

2. **Charge of DNA**: Since DNA is negatively charged, it will migrate towards the positive electrode (anode) when an electric current is applied. This means that the first option stating that DNA migrates towards the negative electrode is incorrect.

3. **Size and Migration Rate**: The migration rate of DNA fragments in agarose gel is inversely proportional to their size. This means that smaller DNA fragments will migrate faster than larger ones. Therefore, the statement that larger molecules migrate faster than smaller molecules is also incorrect.

4. **Visualization of DNA**: Ethidium bromide is a common stain used to visualize DNA fragments in agarose gel after electrophoresis. When exposed to UV light, ethidium bromide intercalates between the bases of the DNA and fluoresces, allowing the DNA bands to be seen. This makes the third statement correct.

5. **Color of DNA Bands under UV Light**: When DNA bands stained with ethidium bromide are exposed to UV light, they appear orange, not pink. Thus, the fourth statement regarding the color of the bands is incorrect.

6. **Conclusion**: Based on the analysis, the correct statement regarding agarose gel electrophoresis is that ethidium bromide can be used to visualize the DNA fragment.

### Final Answer:
The correct option is that ethidium bromide can be used to visualize the DNA fragment.

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