Suppose one restriction enzyme (enzyme A) makes two cuts in a circular DNA molecule, and another restriction enzyme (enzyme B) makes one cut in that same DNA.The cuts are not in the same place, and the cut fragments are not exactly the same size.The restriction digestion is set up on an electrophoresis gel.How many bands should the gel pick up if only enzyme A is used in the restriction digestion?
A) Two
B) Three
C) Four
D) Five
E) Six

Question

Quizplus · Accepted Answer

When enzyme A makes two cuts in a circular DNA molecule, it linearizes the circle and then cuts it one more time, resulting in two linear fragments. These fragments will migrate as two distinct bands on an electrophoresis gel.

Suppose One Restriction Enzyme (Enzyme A) Makes Two Cuts in a Circular