Question

Why are dna fragments with more base pairs found near the sample wells (origin) and the lower number of bp fragments found near the anode?

Answer 1

Gel electrophoresis is a separating technique that is usually used in the laboratory to separate DNA fragments on the basis of their sizes. DNA are typically loaded into one side of the gel called the well and electric force will be applied to separate the fragments. DNA fragments with more base pairs are found near the sample well compare to the anode because larger DNA fragments are not able to move through the gel at a faster rate like the ones with few number of base pair. Because DNA are negatively charged they move toward the anode, but all DNA fragments have the same amount of charge per mass, thus, small fragments move faster away from the well.