DNA polymerases are the enzymes that replicate DNA in living cells. They do this by adding individual nucleotides to the 3-prime hydroxl group of a strand of DNA. The process uses a complementary, single strand of DNA as a template.
The energy required to drive the reaction comes from cutting high energy phosphate bonds on the nucleotide-triphosphate's used as the source of the nucleotides needed in the reaction.
DNA* is the information molecule of the cell.
Ribonucleic acids, also called RNA, perform multiple important roles in living cells. RNA is needed for protein synthesis and DNA