Question

Which of the following statements about primers are correct? Select all that apply.

A. They are synthesized by an enzyme called primase.

B. They provide a 3-OH group for attachment of DNA nucleotides.

C. They are needed for the start of DNA synthesis.

D. They are synthesized by DNA polymerase α.

Answer 1

A. A primer is a short nucleic acid sequence that provides a starting point for DNA synthesis. They are also known as short strands of RNA . They are synthesized by an enzyme called primase a type of RNA polymerase before replication occurs.

B.The DNA polymerase add nucleotides to the 3 ' end of a polynucleotide chain .The polymerase catalyzes the nucleophilic attack of the 3'- hydroxyl group terminus of the polynucleotide chain on the alpha phosphate group of triphosphate nucleotide which is to be added.

C. Primer is required for DNA synthesis or replication because the enzymes that catalyze this process, DNA polymerases to new nucleotides can be added to existing DNA.

D. DNA polymerase alpha synthesize primer for the attachment of triphosphate of nucleotide to the other end .