A student dispensed three identical samples of closed circular DNA to three test tubes. Tube A served as a control. Both tubes B and C received equal amounts of type I topoisomerase; however, the reaction in tube C was allowed to incubate longer
When the contents of all tubes were run on a gel, all tubes showed supercoiled DNA with equally minimal amounts of relaxed DNA. The best conclusion the student should make is that the topoisomerase:
A. catalyzed the reaction so efficiently, the extra time for tube C wasn't required.
B supercoiled the DNA efficiently.
C. the topoisomerase relaxed the DNA efficiently.
D. was denatured and not working properly.
E. was type II, not type I.
D
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