A) is nonexistent because DNA fragments differ widely in charge.
B) depends on separation of similar charge/mass ratio on the basis of size.
C) depends on separation of identical size on the basis of charge/mass ratio.
D) is nonexistent because DNA fragments have no net charge.

A) They attack RNA, not DNA.
B) They can produce "sticky ends".
C) They attack single-stranded sequences only.
D) They do not display sequence specificity in their site of attack.

A) They cut DNA in the middle of specific sequences.
B) They cut DNA independent of the source of the DNA.
C) They often generate single stranded tails or "sticky ends".
D) There are a large variety of them commercially available.
E) All of these traits make restriction enzymes useful.