Transcription is the process of copying genetic information from DNA to RNA. DNA uncoils, an enzyme called RNA polymerase binds to the DNA coding strand and transcribes it to make a pre-mRNA which will later be modified. When the RNA molecule is synthesized next to a strand of DNA, complementary nucleotides bond as in a double-stranded DNA molecule, with one exception, RNA contains uracil (U) nucleotides in place of thymine (T) nucleotides.