Multiple Choice
What is the role of DNA ligase during DNA replication?
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17. Mutation, Repair, and Recombination
DNA Repair
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What is the role of DNA ligase in DNA replication?
A
It joins Okazaki fragments by forming phosphodiester bonds between adjacent DNA fragments on the lagging strand.
B
It removes RNA primers from the lagging strand.
C
It synthesizes RNA primers to initiate DNA synthesis.
D
It unwinds the DNA double helix to allow replication to occur.
Verified step by step guidance1
Understand that DNA replication involves synthesizing new DNA strands complementary to the original strands, with the leading strand synthesized continuously and the lagging strand synthesized in short fragments called Okazaki fragments.
Recognize that Okazaki fragments are initially separate pieces of DNA that need to be joined together to form a continuous strand on the lagging strand.
Recall that DNA ligase is the enzyme responsible for joining these Okazaki fragments by catalyzing the formation of phosphodiester bonds between the 3' hydroxyl end of one fragment and the 5' phosphate end of the next fragment.
Differentiate the role of DNA ligase from other enzymes involved in replication, such as DNA polymerase (which synthesizes DNA), primase (which synthesizes RNA primers), and helicase (which unwinds the DNA helix).
Conclude that the primary role of DNA ligase during DNA replication is to seal the nicks between Okazaki fragments, ensuring the lagging strand becomes a continuous DNA molecule.
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