This is the five end of the single strand shown above and this is the five and this is the three end of the single stranded DNA molecule shown below and they're connected via hydrogen bonds between our nitrogenous bases. Now this is our RNA polymerase as well as our initiation factors. And as the initiation factors move across eventually they come across a region, a sequence of DNA nucleotides known as the promoter region that basically signals our RNA polymerase to begin unwinding and to begin the synthesis process. So when this reaches this region basically the RNA polymerase combines with this initiation factor with these proteins and it's the RNA polymerase itself that actually unwinds these two molecules, unwinds the two single stranded DNA molecules and creates a bubble that is known as the transcription bubble and we'll discuss that in detail in just a moment. So basically one important difference between DNA polymerase and RNA polymerase is that DNA polymerase itself cannot actually unwind the double helix of our DNA but the RNA molecule, the RNA polymerase can in fact itself unwind our molecule. Recall that in our discussion on DNA replication a special type of enzyme known as DNA helicase actually has to unwind the double helix.