During agarose gel electrophoresis , DNA moves

Options

A. towards anode , as it is negatively charged .
B. towards anode , as it is positively charged .
C. towards cathode ,as it is negatively charged .
D. towards cathode ,as it is positively charged .

Answer

### Step-by-Step Solution:

1. **Understanding the Setup**: In agarose gel electrophoresis, a gel matrix is used to separate DNA fragments based on their size. The gel is placed in an electrophoresis chamber with two electrodes: an anode (positive terminal) and a cathode (negative terminal).

2. **Charge of DNA**: DNA molecules are negatively charged due to the presence of phosphate groups in their structure. This means that when an electric field is applied, the DNA will migrate towards the positive electrode.

3. **Direction of Movement**: Since DNA is negatively charged, it will move towards the anode, which is positively charged. This is because opposite charges attract each other.

4. **Evaluating Options**:
- **Option 1**: "Toward the anode as it is negatively charged" - This is incorrect because the anode is positively charged.
- **Option 2**: "Toward anode as it is positively charged" - This is correct because DNA moves towards the positive charge.
- **Option 3**: "Toward the cathode as it is negatively charged" - This is incorrect because DNA does not move towards the negative charge.
- **Option 4**: "Toward the cathode as it is positively charged" - This is also incorrect since the cathode is negatively charged.

5. **Conclusion**: The correct answer is that during agarose gel electrophoresis, DNA moves toward the anode because it is positively charged.

### Final Answer:
**DNA moves toward the anode as it is positively charged.**

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