Introductory Microbiology

DNA replication

• During DNA replication, the two strands of the double helix separate as the replication fork, and each strand is used as a template by DNA polymerases to synthesize two new strands of DNA according to the rules of nitrogenous base pairing.
• The result of DNA replication is two new strands of DNA, each having a base sequence complementary to one of the original strands. Because each double stranded DNA molecules contains one original and one new strand, the replication process is called as semi-conservative method. DNA is synthesized in one chemical direction called 5’-3’ (5’ is phosphate ends, 3’ is hydroxyl end of deoxyribose). At the replication fork, the leading strand is synthesized continuously and the lagging strand discontinuously. DNA polymerase proof reads new molecules of DNA and removes mismatched bases before continuing DNA synthesis.