Segments of single-stranded DNA are called template strands.
Gyrase (a type of topoisomerase) relaxes the supercoiled DNA.
Initiator proteins and DNA helicase binds to the DNA at the replication fork and untwist the DNA using energy derived from ATP (adenosine triphosphate).
(Hydrolysis of ATP causes a shape change in DNA helicase)
DNA primase next binds to helicase producing a complex called a primosome (primase is required for synthesis),
Primase synthesizes a short RNA primer of 10-12 nucleotides, to which DNA polymerase III adds nucleotides.