But in this case the RNA polymerase itself can actually unwind our double helix. So this concludes our discussion of initiation. Let's move on to the process of elongation. So elongation is basically the process where our RNA polymerase actually synthesizes the RNA molecule. So once RNA polymerase unwinds the DNA it creates a bubble that is commonly known as our transcription bubble that is shown in the following diagram. So basically what the transcription bubble is it's a region where our two single strands of DNA have been separated and are now exposed.