What are the key components of DNA replication and what are their functions?

Original DNA template; DNA replication requires an existing double stranded DNA to copy. Free DNA nucleotides; free bases (ATCG) that can be added to the new DNA strand. DNA polymerase; the enzyme required that adds new nucleotides to the new DNA strand. Primers; short strands of nucleotides required by polymerase to build the new DNA strand. DNA polymerase cannot start to extend the DNA strand without a primer to start from. Helicase; facilitates the unwinding of the parent DNA strand. Topoisomerase; enzyme that prevents supercoiling as the original DNA strand is unwoundLigase; joins new sections of the DNA strand.