When DNA Fragments are Separated by Gel Electrophoresis

Question

When DNA fragments are separated by gel electrophoresis:
A) smaller fragments migrate further on the gel than larger fragments.
B) larger fragments migrate further on the gel than smaller fragments.
C) fragments that contain larger amounts of purines, relative to pyrimadines, migrate further.
D) fragments that contain many G-C pairs, relative to A-T pairs, migrate further.
E) all fragments containing genes with related functions migrate to an identical spot on the gel.

Accepted Answer

Smaller fragments have less resistance and migrate faster through the gel matrix, resulting in them traveling further than larger fragments.

Answer: D
 Fragments that contain more G-C pairs have a stronger intermolecular base pairing, resulting in a slower migration rate through the gel matrix, which results in the fragments with more A-T pairs traveling further.

Therefore, the best choices are A and D.