Multiple Choice
The building blocks of nucleic acids are monomers called:
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1. Introduction to Biochemistry
Nucleic Acids
Multiple Choice
In nucleic acid synthesis, which enzyme catalyzes the formation of phosphodiester bonds to join individual nucleotides into a growing DNA or RNA strand?
A
DNA ligase
B
Topoisomerase
C
Helicase
D
DNA (or RNA) polymerase
Verified step by step guidance1
Understand the role of each enzyme listed in the problem: DNA ligase, Topoisomerase, Helicase, and DNA (or RNA) polymerase.
Recall that DNA ligase is responsible for joining Okazaki fragments by forming phosphodiester bonds between DNA fragments, but it does not synthesize the strand continuously.
Recognize that Topoisomerase relieves the torsional strain ahead of the replication fork by cutting and rejoining DNA strands, but it does not catalyze nucleotide addition.
Know that Helicase unwinds the double-stranded DNA to provide single-stranded templates for synthesis, but it does not form phosphodiester bonds.
Identify that DNA (or RNA) polymerase catalyzes the formation of phosphodiester bonds by adding nucleotides to the 3' end of the growing DNA or RNA strand, thus synthesizing the nucleic acid chain.
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