Which of the following enzymes is mainly responsible for the removal of RNA primers during DNA replication in prokaryotes?

Correct answer: (a) DNA polymerase I

Explanation

DNA replication starts from short RNA primers made by primase. In prokaryotes, these primers are later removed by DNA polymerase I, which has a 5′→3′ exonuclease activity. It removes the RNA nucleotides one by one and fills the gaps with DNA.

• DNA ligase then seals the remaining nicks in the backbone, joining the fragments.
• Helicase unwinds the double helix.
• Primase makes the primers; it does not remove them.

In prokaryotes, DNA polymerase III is the main enzyme that builds the new strands.