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HW1.pdf × Search Textbook Solutions Secure 3838-dt-content-rid-72034087 1/courses/11369 11451 11506.201810/HW1.pdf 7. For each of the circular DNAs described below, indicate a location (1, 2, or 3) that the DNA would migrate on an agarose gel. Detergent can inactivate and remove nucleosome proteins. Hint. Nucleosome assembly in the absence of topoisomerase II can introduce negative supercoiling to DNA. You should justify your answers to get a full credit. (12 pt) A. Relaxed circular DNA B. Initiate nucleosome assembly without topoisomerase II and then treat the sample with detergent before running the products on an agarose gel. C. Add topoisomerase II to the previous reaction in B but prevent additional nucleosome assembly. Add detergent before running the products on an agarose gel D. Add topoisomerase II to the reaction described in B and allow additional nucleosome assembly. Add detergent before running the products on an agarose gel 8. The figure shown below is about the effect of salt and GC content on Tm of DNA double helix. Answer whether each of following statement is true information that can be inferred from results in the figure. If the answer is F, please justify your answer (15 pt) or false (F) based on A. Increasing heat can denature DNA molecules 12:33 PM 2/3/2013Explanation / Answer
since negative charge is on the side of site 1, dna wound move in the direction of site 1 to site 3.
1) relaxed circular DNA occupies larger space than coiled or super coiled DNA and hence would appear close to SITE A.
2) nucleosome assemply will initiate negative supercoiling in absence of topoisomerase II and hence will again result in formation of circular uncoiled DNA and hence will again show close to Site A.
3) In presence of topo isomerase and nucleosome, DNA would be super coiled and move easily in the gel and hence will be observed at site 2.
4) when further nucleosome is added, it would result in further coiling and hence will appear at SITE 3.
Thank you.
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