What function do RNA primers perform during DNA Replication?

Question

A. fill in gaps between groups of nucleotides on the lagging strand

B. provide sites for nucleotides addition along both strands

C. Stabilize the DNA molecule to prevent breakage

D correct errors made during DNA-strand synthesis

Answer 1

The correct answer for this question is B, provide sites for nucleotide addition along both strands. The reason for this is that DNA polymerase is unable to begin nucleotide synthesis. RNA polymerase, in contrast, is able to begin synthesis without an existing template to build off of. Therefore, when DNA synthesis is occurring, RNA primase will start the process of synthesis on both the leading and lagging strand, creating the RNA primer with an exposed 3' end to which DNA polymerase can add DNA. Once synthesis is complete, the RNA primer is removed and replaced by DNA via DNA polymerase I and the gap between these two is filled in by DNA ligase, thus "gluing" together these two sections into a single, cohesive length of DNA.