Multiple Choice
In the overview of DNA replication, what is the primary role of DNA ligase?
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8. DNA Replication
Overview of DNA Replication
Multiple Choice
In DNA replication, what is the primary role of DNA ligase?
A
It adds nucleotides to the growing DNA strand in the to direction.
B
It seals nicks in the sugar-phosphate backbone by joining Okazaki fragments on the lagging strand.
C
It synthesizes short RNA primers needed to initiate DNA synthesis.
D
It unwinds the DNA double helix ahead of the replication fork by breaking hydrogen bonds.
Verified step by step guidance1
Understand the process of DNA replication, which involves synthesizing new DNA strands complementary to the original template strands.
Recognize that DNA replication occurs in a 5' to 3' direction, with the leading strand synthesized continuously and the lagging strand synthesized discontinuously in short segments called Okazaki fragments.
Identify the role of DNA ligase specifically in the lagging strand synthesis, where it joins these Okazaki fragments by sealing the nicks in the sugar-phosphate backbone.
Differentiate DNA ligase's function from other enzymes: DNA polymerase adds nucleotides, primase synthesizes RNA primers, and helicase unwinds the DNA helix.
Conclude that DNA ligase's primary role is to catalyze the formation of phosphodiester bonds between adjacent DNA fragments, ensuring the integrity and continuity of the newly synthesized DNA strand.
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