DNA Replication Easy as 1,2,3 !!! Step 1 • DNA strand unwinds and the hydrogen bond is broken between the two sides of the ladder. Step 2 • An enzyme DNA polymerase will use the original strand of DNA to match new complimentary nucleotides to the original strands.. Step 2 Illustrated Step 3 • New nucleotides would be put in place on both old strands to produce two new DNA molecules.