#Id: 2302
#Unit 3. Fundamental Processes
As RNA polymerase moves along the DNA template, it unwinds the duplex at the front of the bubble (the unwinding point), and the DNA automatically reforms the double helix at the back (the rewinding point).
1. The length of the transcription bubble is 12 to 14 bp, but the length of the RNA–DNA hybrid within the bubble is only 8 to 9 bp.
2. As the enzyme moves along the template, the DNA duplex reforms, and the RNA is displaced as a free polynucleotide chain.
3. The last 14 ribonucleotides in the growing RNA are complexed with the DNA and/or the enzyme at any given moment.
