What are Okazaki fragments? What role do they serve in DNA metabolism?

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Accepted Answer

All right. Hello everyone. So this question is asking us which of the following is true about Okazaki fragments and their role in DNA replication. So here we have four different answer choices labeled a through D describing whether or not Okazaki fragments are long or short strands of DNA as well as their proposed role in either the leading strand or the lagging strand. Now, let's talk about what the words leading and lagging strand actually mean recall that during DNA replication, DNA is unwound. So we're going from the characteristic double strand confirmation into two single stranded parts, right? This is because DNA polymerase is going to bind to each individual strand and create two new double helices after replication. No DNA that's double stranded is oriented in opposite directions, meaning that one strand runs from five prime to three prime and the other runs from three prime to five prime. Now, DNA polymerase can only create a new strand running from five prime to three prime. And so the opposite strand or the strand running in the opposite direction from three prime to five prime is known as the leading strand. This is because DNA polymerase can bind to the leading strand and synthesize smoothly. Right. In other words, only one primer is needed to go ahead and synthesize the complement of the leading strand. This is why the strand running from five prime to three prime is known as the lagging strand because it cannot or rather DNA polymerase cannot elongate the new strand as it would. In the leading strand, there are going to be interruptions because of the directionality of the lagging strand. Multiple RNA primers need to be synthesized throughout the lagging strand so that DNA polymerase can continue replicating it. So in other words, the lagging strand is going to grow in segments and those fragments are known as Okazaki fragments, oops. And so those Okazaki fragments are eventually going to be bound together by a DNA ligase enzyme. Now, the Okazaki fragments themselves are quite short by definition. This is because new RN A primers are constantly being added to continue DNA replication from the lagging strand. So essentially we can conclude that Okazaki fragments are short segments, excuse me, segments of DNA synthesized to lengthen the lagging strand during the process of DNA replication. So the synthesis of Okazaki fragments allows for replication to continue. This means that our answer is going to be option c in the multiple choice. And so with that being said, thank you so very much for watching and I hope you found this helpful

What are Okazaki fragments? What role do they serve in DNA metabolism?

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Key Concepts

Okazaki Fragments

DNA Replication

Lagging Strand