Refer to an experiment that was performed to separate DNA fragments from four samples radioactively labeled with 32 P. The fragments were separated by gel electrophoresis.
(A) relative amounts of radioactivity in the DNA
(B) number of cleavage points per fragment
(C) size of each fragment
(D) overall positive charge of each fragment
(E) solubility of each fragment
Answer: C
The electrophoretic separation of the pieces of DNA in each of the four samples was achieved because of differential migration of the DNA fragments in an electric field. This differential migration was caused by the
(A) relative amounts of radioactivity in the DNA
(B) number of cleavage points per fragment
(C) size of each fragment
(D) overall positive charge of each fragment
(E) solubility of each fragment
Answer: C