Polymerases are enzymes that play a crucial role in the process of DNA and RNA synthesis. They work by adding nucleotide units to a growing chain, which is essential for replicating genetic material during cell division and for synthesizing RNA from a DNA template. There are different types of polymerases, such as DNA polymerase and RNA polymerase, each with specific functions. DNA polymerase is responsible for copying DNA, while RNA polymerase synthesizes RNA from a DNA template. These enzymes are vital for maintaining the integrity of genetic information and enabling cellular functions.