In agarose gel electrophoresis, DNA molecules are separated on the basic of their

Options

A. size only
B. charge only
C. charge to size ratio
D. all of these

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. The gel acts as a medium through which DNA molecules can move when an electric current is applied.

2. **Charge of DNA**: DNA molecules are negatively charged due to their phosphate backbone. When an electric field is applied, the negatively charged DNA fragments will migrate towards the positive electrode (anode).

3. **Movement of DNA Fragments**: In the gel, smaller DNA fragments can move more easily through the pores of the agarose matrix compared to larger fragments. This is because the agarose gel acts like a sieve.

4. **Sieving Effect**: The agarose gel creates a sieving effect, meaning that smaller fragments can navigate through the gel's pores more effectively than larger fragments. As a result, smaller fragments will travel farther in the gel towards the anode.

5. **Conclusion**: Therefore, in agarose gel electrophoresis, DNA molecules are separated primarily based on their size. Smaller fragments move faster and farther than larger fragments.

**Final Answer**: In agarose gel electrophoresis, DNA molecules are separated on the basis of their size.

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