Which enzyme is responsible for laying down RNA primers during DNA replication?

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Multiple Choice

Which enzyme is responsible for laying down RNA primers during DNA replication?

Explanation:
Initiation of DNA synthesis requires an RNA primer because DNA polymerases cannot start a new strand from scratch; they can only add nucleotides to an existing 3' hydroxyl group. The enzyme that creates this primer is primase, an RNA polymerase that lays down a short RNA sequence to provide that 3' end for DNA polymerase to extend. On the leading strand, one primer suffices, while on the lagging strand primase repeatedly lays down primers for each Okazaki fragment, enabling discontinuous synthesis. After extension, the RNA primers are removed and replaced with DNA, and the nicks are sealed by ligase. In bacteria, primase is a separate enzyme (DnaG); in eukaryotes, the primase activity is part of the DNA polymerase alpha-primase complex.

Initiation of DNA synthesis requires an RNA primer because DNA polymerases cannot start a new strand from scratch; they can only add nucleotides to an existing 3' hydroxyl group. The enzyme that creates this primer is primase, an RNA polymerase that lays down a short RNA sequence to provide that 3' end for DNA polymerase to extend. On the leading strand, one primer suffices, while on the lagging strand primase repeatedly lays down primers for each Okazaki fragment, enabling discontinuous synthesis. After extension, the RNA primers are removed and replaced with DNA, and the nicks are sealed by ligase. In bacteria, primase is a separate enzyme (DnaG); in eukaryotes, the primase activity is part of the DNA polymerase alpha-primase complex.

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