Describe the process of DNA replication

In DNA replication, first the hydrogen bonds between the nitrogenous bases are broken catalysed by the enzyme helicase, causing the DNA double helix to unwind and unzip, leaving the nitrogenous bases exposed. Free bases in the nucleus then form hydrogen bonds with the exposed bases, following complementary base pairing rules, so guanine binds to cystine and thymine binds to adenine. The sugar phosphate backbone is then formed in the 5' to 3' direction, with the phosphodiester bonds formed catalysed by the enzyme DNA polymerase. This forms a new double helix. DNA replication is semi conservative as one strand is from the original DNA molecule and one stand is newly synthesized.