Which enzyme removes RNA primers and replaces them with DNA during bacterial DNA replication?

DNA polymerase I removes RNA primers and replaces them with DNA during bacterial DNA replication.

In Escherichia coli, DNA polymerase I has a 5′-to-3′ exonuclease activity that removes RNA primer segments and a polymerase activity that fills the resulting gaps with DNA. The remaining nick in the sugar-phosphate backbone is sealed by DNA ligase.

DNA polymerase III is the main enzyme that copies the bacterial chromosome, so it is a common alternative answer. Polymerase I has a different but essential cleanup role after replication machinery has extended the new strands.

Arthur Kornberg discovered DNA polymerase I in 1956 and received the 1959 Nobel Prize in Physiology or Medicine for work on the biological synthesis of nucleic acids. The enzyme became a foundational tool in molecular biology.