Final answer:
DNA polymerases are crucial for DNA replication and repair in both prokaryotic and eukaryotic cells. They function by adding nucleotides to the growing DNA chain and provide proofreading to minimize errors. The replication process also includes a set of specialized enzymes that work together to ensure accurate and complete DNA synthesis.
Step-by-step explanation:
DNA Polymerases in DNA Replication and Repair
DNA polymerases are crucial enzymes in both DNA replication and repair reactions. In prokaryotes, key types include DNA pol I, DNA pol II, and DNA pol III, with DNA pol III being essential for DNA strand synthesis. These polymerases add deoxyribonucleotides to the 3'-OH end of a growing DNA chain, requiring energy from the hydrolysis of triphosphate nucleotides.
In eukaryotes, the DNA replication process involves enzymes such as DNA polymerase alpha (similar to DNA pol I), DNA polymerase delta, and DNA polymerase epsilon. DNA replication in eukaryotes involves a complex system of proteins and enzymes, collectively called the replisome. Replication starts at specific sequences called origins of replication and proceeds with the help of various enzymes, including helicase, DNA ligase, and potentially telomerase in eukaryotic cells to protect chromosome ends.
During replication, DNA polymerases not only synthesize new strands but also perform proofreading to ensure that the correct bases are incorporated. Errors that do slip through are often corrected by a mismatch repair mechanism. Overall, the process is semiconservative, meaning each daughter DNA molecule is comprised of one pre-existing and one newly synthesized strand.