Multiple Choice
During DNA replication, which enzyme is primarily responsible for unwinding ("unzipping") the DNA double helix 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 helicase at the replication fork?
A
It adds nucleotides to the growing DNA strand in the to direction.
B
It joins Okazaki fragments by forming phosphodiester bonds between adjacent DNA segments.
C
It unwinds the parental double helix by breaking hydrogen bonds between complementary bases.
D
It synthesizes short RNA primers to initiate DNA synthesis on each template strand.
Verified step by step guidance1
Understand the context of DNA replication, which involves unwinding the double helix and synthesizing new strands complementary to each original strand.
Identify the replication fork as the site where the parental DNA strands are separated to allow replication to occur.
Recall that helicase is an enzyme specifically responsible for unwinding the parental double helix by breaking the hydrogen bonds between complementary base pairs, thus separating the two strands.
Differentiate helicase's role from other enzymes: DNA polymerase adds nucleotides, ligase joins Okazaki fragments, and primase synthesizes RNA primers.
Conclude that the primary role of helicase at the replication fork is to unwind the parental DNA strands, enabling the replication machinery to access the single-stranded templates.
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