Two DNA sequences,each 48 kb in size,are treated with the same restriction enzyme.There is only one site for this restriction enzyme on each of these sequences.Digests are separated by gel electrophoresis.Sequence A shows ONE band that is 48 kb in size.Sequence B shows TWO bands,one 30 kb and the other 18 kb in size.What can you conclude from these data?
A)They are identical sequences.
B)Both sequences are linear.
C)Sequence A is circular;sequence B is linear.
D)Sequence A is linear;sequence B is circular.

Question

Quizplus · Accepted Answer

Sequence A must be circular because the restriction enzyme cut it only once but it still appears as a single band, indicating the DNA remained intact as a circle. Sequence B, showing two distinct bands after being cut once, must be linear, as the cut resulted in two separate pieces of DNA.

Two DNA Sequences,each 48 Kb in Size,are Treated with the Same