Helicase breaks apart hydrogen bonds which cause it to unwind. This exposes them so they can be read by RNA polymerase. RNA polymerase binds to template strand at beginning of sequence to be copied. Free nucleotide align opposite the template strand, RNA polymerase moves along DNA which form bonds that add the RNA nucelotides one at a time. Behind the RNA polymerase the DNA strands join up to reform the double helix.