Describe the process of transcription

Transcription takes place in the nucleus and is the first stage of protein synthesis. RNA polymerase attaches to the DNA double helix at the promoter sequence and unwinds the helix by breaking the hydrogen bonds. Complementary free RNA nucleotides are lined up alongside the exposed bases and are joined together by RNA polymerase. The RNA polymerase continues down the double helix forming the mRNA molecule, and once the polymerase has passed, the two strands of DNA rejoin to form the helix. Once a stop signal is reached, RNA polymerase detaches from the DNA and the mRNA molecule exits the nucleus through a nuclear pore and into the cytoplasm.