You are asked to give a classroom demonstration of DNA supercoiling. To do so, you take two different colored pieces of rubber tubing, twist them very tightly and excessively around each other and join the ends of the tubing appropriately. Next, you relieve the supercoiling by breaking one strand and unwinding it. In this demonstration, the breaking and unwinding to relieve the supercoiling simulates the action of

A. polymerases.
B. exonucleases.
C. primases.
D. topoisomerases.
E. ligases.


Answer: D

Biology & Microbiology

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