Multiple Choice
During DNA replication, what enzyme is responsible for “unzipping” the double helix by separating the two DNA strands at 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 role of DNA polymerase?
A
It unwinds the DNA double helix ahead of the replication fork by breaking hydrogen bonds.
B
It joins Okazaki fragments together by forming phosphodiester bonds between them.
C
It lays down short RNA primers to provide a free 3′ hydroxyl group for DNA synthesis.
D
It synthesizes a new DNA strand by adding nucleotides to the 3′ end using the template strand.
Verified step by step guidance1
Understand the overall process of DNA replication, which involves unwinding the DNA double helix, synthesizing new strands, and joining fragments.
Identify the specific functions of key enzymes involved: helicase unwinds the DNA, primase lays down RNA primers, DNA ligase joins Okazaki fragments, and DNA polymerase synthesizes new DNA strands.
Focus on the role of DNA polymerase, which is to add nucleotides complementary to the template strand, extending the new DNA strand in the 5' to 3' direction by attaching nucleotides to the 3' hydroxyl end.
Recall that DNA polymerase requires a primer with a free 3' hydroxyl group to begin synthesis, but it does not create the primer itself—that is the role of primase.
Summarize that the primary role of DNA polymerase is to catalyze the formation of phosphodiester bonds between nucleotides, effectively synthesizing the new DNA strand complementary to the template.
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