ABSTRACT
Genomic DNA in cells is present as Watson-Crick base-paired double helices. During replication, this duplex structure must be opened so that polymerase enzymes can access the base sequence in order to synthesize new strands of DNA that are complementary in sequence to the original. DNA replication occurs with extremely high delity, with only one base in approximately ten to one hundred million incorrect at the completion of replication. is high accuracy in copying is necessary to prevent mutations of the DNA that can a ect the ability of the cell to survive. It is remarkable that nature can maintain very high delity while copying DNA at a rate of well over one hundred base pairs per second.
