What process ensures that the replication of DNA produces identical copies?

Question

Accepted Answer

Hello, everyone. And welcome back. Our next problem says which of the following statements describes the process that ensures DNA replication produces identical copies. So we're talking about when we make new DNA molecules, how do we ensure that the new copy is identical to the old one? Let's read through our answer. Choices. Choice A says in the DNA replication process, the enzyme RN A prima ensures that each new MRN A molecule is read. So it produces an identical copy of the original DNA because RN A is the one that keeps DNA in check. Hopefully, we can eliminate this one pretty easily. The function of RN A is of course to be that bridge from the genetic code and DNA to the synthesis of proteins. It doesn't check DNA for being identical RN A prima is responsible for synthesizing the RN A primers that are necessary to start off a new DNA strand. So first, a little RN A primer is put on that matches with the very first couple of base pairs or bases of the DNA strand. And then DNA polymerase adds bases on to that. So RN a polymerase or excuse me RN A primate is involved in DNA replication but not in checking, there's an identical copy. It's just sort of the Kickstarter that gets the process going. Now, let's look at choice BB says in the DNA replication process, only leading and lagging strands ensure that each new DNA molecule consists of one original strand and one newly synthesized strand producing identical copies of the original DNA. Well, the second half of our answer here is a good description of this process that ensures we have identical molecules. Each DNA molecule, each new one consists of one original and one newly synthesized. So one template strand and then one new strand which has the result of producing identical copies. But it is not the fact that there are leading and lagging strands leading and lagging strands are of course a result of the fact that DNA polymerase which makes the new strand can only synthesize, can only add on bases to the three prime end of the new strand. Since it can only synthesize the new strand in the five prime to three prime direction, then the lagging strand in which the template is five prime to three prime is synthesized in discontinuous fragments. So discontinuous five prime to three prime fragments. So of course, that process goes more slowly than when the template is in a three prime to five prime direction. And new bases can just be continuously added on. But again, that's not ensuring that we have two identical copies, that's just dealing with the directionality of DNA polymeric. So now let's look at to C in the DNA replication process. Only DNA prelim two ensures that each new DNA molecule consists of one original strand and one newly synthesized daughter strand producing identical copies of the original DNA. Well, again, we have the correct description of how the identical nature of the new copy is ensured that it's this process where you have one original and one new strand. But it is not DNA prelimerase too. That does this DNA prelimerase two is involved in proofreading and repair of DNA. And it's not responsible for synthesizing the new strand. It's DNA poli three, put that at the bottom. DNA polymerase three is the one that actually makes those new strands. So this one maybe is a bit tricky because we think of DNA polymerase two and its proofreading and repair functions as something that ensures correct copying. But that's not what our question is asking for. It's asking why are there two identical copies as the product here? So we know by elimination choice D much be correct. So let's read through this. It says DNA replication is a semiconservative process that ensures that each new DNA molecule consists of one original strand and one newly synthesized strand producing identical copies of the original DNA. And yes, this is the key to the whole thing. Choice D that we are able to use an original strand as a template to ensure that the new copy is identical to the old copy because we have this semiconservative process. So choice D is our correct answer here. See you in the next video.

What process ensures that the replication of DNA produces identical copies?

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Key Concepts

DNA Replication

Base Pairing Rules

DNA Polymerase