e a scientist treated a closed-circular DNA sample with topoisomerases to prepar
ID: 267836 • Letter: E
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e a scientist treated a closed-circular DNA sample with topoisomerases to prepare samples with Map Su different superhelical densities (o) The scientist ran the samples on agarose gels treated with chloroquine at 0.5 ?/mL (Gel A) and 5 ?mL (Gel B). In each sample, completely relaxed (nicked) DNA migrated to position N, whereas highly supercoiled DNA migrated to position X [ Gel Al Gelb] Average ? Average ? ALK ALk Select reasonable explanations for the presence of multiple bands in many of the samples Some DNA species in a sample are positively supercoiled and others are negatively supercoiled DNA isolation introduces small numbers of single-strand on double-strand breaks in some closed-circular molecules in a sample Chloroquine addition affects topoisomerase activity, resulting in a mixture of topoisomers Continued below Endonucleases degrade some samples, which reduces the molecular weight of the affected sample Some DNA species in a relaxed, closed-circle state are completely relaxed, whereas others are slightly underwound or overwound Previous ? Give Up & View Solution O Check Answer Next Exit HintExplanation / Answer
1) C. Chloroquine addition affects topoisomerase activity, resulting in a mixture of topoisomers.
2) E. -0.115
The native DNA is migrated same as the last DNA present on the right side of the gel in the gel A
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