What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? A) It synthesizes RNA nucleotides to make a primer.B) It joins Okazaki fragments together.C) It unwinds the parental double helix.D) It stabilizes the unwound parental DNA.
The correct answer is B) It joins Okazaki fragments together
The correct answer is B) It joins Okazaki fragments together.
During DNA replication, DNA polymerase is responsible for synthesizing the new strands of DNA. However, the two strands of DNA in the double helix have opposite orientations, which means that one strand (the leading strand) can be continuously synthesized in the 5′ to 3′ direction, while the other strand (the lagging strand) is synthesized in short fragments called Okazaki fragments.
After DNA polymerase finishes synthesizing an Okazaki fragment on the lagging strand, there are small gaps remaining between the fragments. These gaps are generated because DNA polymerase can only add nucleotides in the 5′ to 3′ direction, and it needs a primer to start the synthesis process.
This is where DNA ligase comes in. DNA ligase is an enzyme that has the ability to join the Okazaki fragments together. It catalyzes the formation of phosphodiester bonds between adjacent nucleotides, sealing the gaps left between the fragments. In other words, DNA ligase acts like a “glue” that connects the Okazaki fragments and completes the synthesis of the lagging strand during DNA replication.
Therefore, the correct role of DNA ligase in the elongation of the lagging strand during DNA replication is to join the Okazaki fragments together.
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