Question

Having become an expert on gel electrophoresis, you are asked to examine a gel for a colleague. Where would you find the smallest segments of DNA?

• A. Near the positive electrode, farthest away from the wells
• B. Near the negative electrode, close to the wells
• C. Near the negative electrode, farthest away from the wells
• D. Near the middle, they tend to slow down after the first few minutes

Answer 1

The correct option is A Near the positive electrode, farthest away from the wells

Since DNA is itself negatively charged, it would move towards the positive electrode. In gel electrophoresis, DNA fragments are separated on the basis of charge and masses. Thus, smaller the DNA fragment farther it moves from the well.

So, the correct option is A.