Multiple Choice
During DNA replication, what is the primary role of DNA gyrase (a bacterial type II topoisomerase) ahead of the replication fork?
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8. DNA Replication
Overview of DNA Replication
Multiple Choice
In the overview of DNA replication, what is the primary function of DNA polymerase?
A
It unwinds the DNA double helix by breaking hydrogen bonds between base pairs.
B
It lays down short RNA primers to provide a free 3′-OH group for DNA synthesis to begin.
C
It synthesizes new DNA strands by adding nucleotides to the 3′ end using a template strand.
D
It joins Okazaki fragments together by forming phosphodiester bonds in the sugar-phosphate backbone.
Verified step by step guidance1
Understand the role of DNA polymerase in DNA replication, which is the process of copying the DNA molecule to produce two identical DNA strands.
Recall that DNA polymerase cannot initiate synthesis on its own; it requires a primer with a free 3′-OH group to add nucleotides.
Recognize that DNA polymerase adds nucleotides complementary to the template strand, extending the new DNA strand in the 5′ to 3′ direction by attaching nucleotides to the 3′ end.
Differentiate DNA polymerase's function from other enzymes involved in replication, such as helicase (which unwinds DNA), primase (which lays down RNA primers), and DNA ligase (which joins Okazaki fragments).
Conclude that the primary function of DNA polymerase is to synthesize new DNA strands by adding nucleotides to the 3′ end using the template strand as a guide.
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