DNA replication occurs in the nucleus of eukaryotic cells and in the cytoplasm of prokaryotic cells. In both cells, the process involves a variety of steps and enzymes.
DNA replication begins with the double stranded DNA being unzipped into two single strands by the enzyme helicase. Next, DNA polymerase attaches itself to each single strand of DNA. The DNA polymerase moves slowly along the single strands of DNA and adds complimentary DNA nucleotides to the DNA strands. Once the DNA polymerase reaches the end of each single stranded DNA it has created two semi-conserved double stranded DNA molecules. The new DNA can then be inserted into new daughter cells that were created by mitosis.