Answer:
DNA polymerase requires a primer sequence to provide a free 3 prime hydroxyl functional group to which the new DNA nucleotide can be added.
Step-by-step explanation:
DNA polymerase is the enzyme of DNA replication that can not start the formation of new DNA strand de novo but can elongate the existing primer. The enzyme adds new deoxyribonucleotides to the free 3' OH (hydroxyl) group of the existing primer by catalyzing the formation of a phosphodiester bond.
The free 3' OH group present at the 3' end of the growing strand or primer serves as a nucleophile and attacks the alpha phosphorus of incoming dNTP resulting in the formation of a phosphodiester bond.