What is the role of DNA primase in replication?

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What is the role of DNA primase in replication?

DNA replication depends on giving DNA polymerase a free 3' end to extend from, which DNA itself cannot provide. DNA primase creates a short RNA primer, providing that essential 3' hydroxyl so DNA polymerase can start adding nucleotides. On the leading strand, a single primer suffices for continuous synthesis, while on the lagging strand primers are laid down repeatedly to start each Okazaki fragment because synthesis proceeds away from the replication fork. After a segment is built, the RNA primer is removed and replaced with DNA, and the gaps are sealed by DNA ligase. Unwinding of DNA is done by helicase, primers are removed by RNase H (and other enzymes in some systems), and sealing is done by ligase, so primase itself is specifically the enzyme that lays down those RNA primers to start DNA synthesis.

DNA replication depends on giving DNA polymerase a free 3' end to extend from, which DNA itself cannot provide. DNA primase creates a short RNA primer, providing that essential 3' hydroxyl so DNA polymerase can start adding nucleotides. On the leading strand, a single primer suffices for continuous synthesis, while on the lagging strand primers are laid down repeatedly to start each Okazaki fragment because synthesis proceeds away from the replication fork. After a segment is built, the RNA primer is removed and replaced with DNA, and the gaps are sealed by DNA ligase. Unwinding of DNA is done by helicase, primers are removed by RNase H (and other enzymes in some systems), and sealing is done by ligase, so primase itself is specifically the enzyme that lays down those RNA primers to start DNA synthesis.

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