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Ch. 12 - DNA Organization in Chromosomes
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All textbooksKlug 12th EditionCh. 12 - DNA Organization in ChromosomesProblem 22

Chapter 12, Problem 22

An article entitled 'Nucleosome Positioning at the Replication Fork' states: 'both the 'old' randomly segregated nucleosomes as well as the 'new' assembled histone octamers rapidly position themselves (within seconds) on the newly replicated DNA strands' [Lucchini et al. (2002)]. Given this statement, how would one compare the distribution of nucleosomes and DNA in newly replicated chromatin? How could one experimentally test the distribution of nucleosomes on newly replicated chromosomes?

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Everyone. Let's take a look at this question together. What are the two activities that occur at the replication fork? So let's recall what the replication fork is. To try to figure out what the two activities that occur there are. So let's go ahead and start off by drawing a diagram of what the replication fork is. And then we can talk about what occurs at that fork. So here we can see a strand of D. N. A. And at this point here is where that fork is, where the two strands separate and we end up with two individual strands that are not in that helical orientation. And so at that fork where the two strands separate, we have two key enzymes that have specific jobs. The first one is D. N. A. The case which is responsible for unwinding the D. N. A helix. So that way we end up with both a leading strand and the lagging strand. And so that separation of the helical structure is done by D. N. A. Hell A case. And the other enzyme that we have is D. N. A limb arrays, which we all know is responsible for the synthesis of D. N. A. For replication. And so these are two activities that occur at that replication fork. So that means that answer choice D. Is the correct answer because we know that at this fork we have D. N. A hell a case which is responsible for unwinding D. N. A. And we have D. N. A polymerase which is responsible for that synthesis of DNA, which is answer choice D D N A. Unwinding and DNA synthesis. So it is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.
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