Which of the given statements is correct in the context of observing DNA separated by agarose gel electrophoresis ?

Options

A. DNA can be seen in visible light
B. DNA can be seen without staining in vis- ible light
C. Ethidium bromide stained DNA can be seen in visible light
D. Ethidium bromide stained DNA can be seen under exposure to UV ligh

Answer

To solve the question regarding the correct statement in the context of observing DNA separated by agarose gel electrophoresis, we can break down the steps as follows:

### Step-by-Step Solution:

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

2. **Setup of the Electrophoresis Apparatus**:
- The gel consists of wells where DNA samples are loaded. The gel is placed in an electrophoresis chamber connected to a power supply, with one end (cathode) being negatively charged and the other end (anode) positively charged.

3. **Movement of DNA**:
- When an electric current is applied, the negatively charged DNA moves towards the positive electrode (anode). Smaller DNA fragments move faster and travel further through the gel compared to larger fragments.

4. **Staining the DNA**:
- Ethidium bromide is a common intercalating agent used to stain DNA. It binds to the DNA and fluoresces under UV light, allowing visualization of the DNA bands.

5. **Visualization Under UV Light**:
- DNA can only be visualized after it has been stained with ethidium bromide and exposed to UV light. This is because ethidium bromide emits fluorescence when bound to DNA, making the bands visible.

6. **Evaluating the Statements**:
- The statements provided in the question likely include options about the visibility of DNA with and without staining, and under what conditions DNA can be seen.
- The correct statement would be that "Ethidium bromide stained DNA can be seen under exposure to UV light."

### Final Answer:
The correct statement in the context of observing DNA separated by agarose gel electrophoresis is that "Ethidium bromide stained DNA can be seen under the exposure to UV light."

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