Multiple Choice
In bacterial DNA replication, what is the primary function of DNA gyrase (a 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 role of DNA ligase?
A
It synthesizes short RNA primers to provide a hydroxyl group for DNA polymerase to begin elongation.
B
It seals nicks in the sugar-phosphate backbone by joining Okazaki fragments on the lagging strand.
C
It adds DNA nucleotides only in the to direction to elongate the new strand.
D
It unwinds the parental double helix ahead of the replication fork by breaking hydrogen bonds between bases.
Verified step by step guidance1
Understand that DNA replication involves synthesizing new DNA strands complementary to the original strands.
Recognize that the lagging strand is synthesized discontinuously in short segments called Okazaki fragments.
Identify that these Okazaki fragments are initially separate and need to be joined to form a continuous strand.
Know that DNA ligase is the enzyme responsible for sealing the nicks between Okazaki fragments by forming phosphodiester bonds in the sugar-phosphate backbone.
Conclude that the primary role of DNA ligase is to join these fragments, ensuring the integrity and continuity of the newly synthesized DNA strand.
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