Question

A dna molecule is cut with two different restriction enzymes known to cleave it only once each. after gel electrophoresis, three different dna fragments are detected. this result means that the original dna molecule was:

Answer 1

Answer: Linear

Explanation: The DNA molecule could be either linear or circular. Now according to the question, since each enzyme is cutting the DNA at one point only, the circular DNA would make two fragments only. It will look like this image shared below. And if its linear, then only it can make three fragments. The case of both linear and circular DNA is mentioned in images shared below.