AP BIOLOGY

Detailed explanation-1: -In living organisms, primers are short strands of RNA. A primer must be synthesized by an enzyme called primase, which is a type of RNA polymerase, before DNA replication can occur.

Detailed explanation-2: -Primase synthesizes RNA primers complementary to the DNA strand. DNA polymerase III extends the primers, adding on to the 3’ end, to make the bulk of the new DNA. RNA primers are removed and replaced with DNA by DNA polymerase I. The gaps between DNA fragments are sealed by DNA ligase.

Detailed explanation-3: -An RNA primer is a short segment of single-stranded RNA used as a binding site for DNA polymerase to initiate DNA replication. DNA polymerase is only able to add nucleotides to an existing nucleotide chain; it cannot “start from scratch, ” and therefore needs the RNA primer to start the process.