Multiple Choice
During DNA replication, what is the primary function of helicase?
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8. DNA Replication
Overview of DNA Replication
Multiple Choice
In the context of DNA replication, what is the primary function of DNA ligase?
A
It adds nucleotides to the growing DNA strand in the 5' to 3' direction using a DNA template.
B
It synthesizes short RNA primers to provide a free 3' end for DNA polymerase to extend.
C
It seals nicks in the sugar-phosphate backbone by forming phosphodiester bonds, joining Okazaki fragments into a continuous DNA strand.
D
It unwinds the DNA double helix ahead of the replication fork by breaking hydrogen bonds between base pairs.
Verified step by step guidance1
Identify the role of DNA ligase in DNA replication by understanding the process of how the DNA strand is synthesized, especially on the lagging strand where Okazaki fragments are formed.
Recall that DNA polymerase synthesizes new DNA strands by adding nucleotides in the 5' to 3' direction but cannot join fragments together directly.
Understand that Okazaki fragments are short DNA segments synthesized discontinuously on the lagging strand, which need to be connected to form a continuous strand.
Recognize that DNA ligase's primary function is to seal the nicks between these Okazaki fragments by catalyzing the formation of phosphodiester bonds in the sugar-phosphate backbone.
Conclude that DNA ligase acts as the enzyme that joins these fragments, ensuring the integrity and continuity of the newly synthesized DNA strand.
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