DNA replication is the process of producing two identical copies from one original DNA molecule. This biological process occurs in all living organisms, and is the basis for biological inheritance. DNA is composed of two strands and each strand of the original DNA molecule serves as template for the production of the complementary strand, a process referred to as semiconservative replication. Cellular proofreading and error-checking mechanisms ensure near perfect fidelity for DNA replication.
First of all, helicase unzips the strand and breaks hydrogen bonds. Then, RNA primase lays down RNA at the 3’ end. Afterwards, DNA poly III lays down DNA nucleotides on the leading and lagging strands. Last but not least, DNA poly I replaces the RNA with DNA, and ligase glues the lagging strand (Okazaki fragments) together using polypeptide bonds.
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