Suppose restriction enzyme A makes two cuts in a linear DNA fragment and restriction enzyme B makes one cut in that same DNA.The cuts are not in the same place, and no two of the cut fragments is exactly the same size.The digested samples are run in an electrophoresis gel.How many bands should the gel pick up if only enzyme A is used in the restriction digest?
A) Two
B) Three
C) Four
D) Five
E) Six

Question

Quizplus · Accepted Answer

If enzyme A makes two cuts and enzyme B makes one cut, then using only enzyme A will result in 3 fragments (assuming no fragments are too small to be detected on the gel). Each of the two cuts from enzyme A will create a separate fragment, and the third fragment will be the remaining piece of DNA between the two cuts. Therefore, the gel should pick up three bands if only enzyme A is used in the restriction digest.

Suppose Restriction Enzyme a Makes Two Cuts in a Linear