Before a cell divides during the process of mitosis, it must duplicate its DNA. Describe the process of DNA replication.

DNA helicase breaks the hydrogen bonds between the two strands of the DNA helix, separating them. Each strand can then act as a template for the synthesis of new DNA. Free nucleotides can then attach to the template, using the complementary base pairing rule (AT and GC). To form the new strand, DNA polymerase joins together adjacent nucleotides and the hydrogen bonds between the two strands reform. This is the process of semi-conservative replication, with the new DNA duplex containing one new strand and the other strand from the original copy.