List the highlights of the three stages of transcription.

• A. Elongation ends at the promoter
• B. Termination occurs before transcription begins
• C. Initiation involves promoter recognition and RNA polymerase binding
• D. All of the above

Answer: (C)

Transcription is organized into three stages, each defined by a key event that sets the process in motion, moves it forward, and then finishes it. The highlight of the initiation stage is promoter recognition and RNA polymerase binding: this is when the enzyme is recruited to the gene by specific promoter elements (with helper factors in organisms like bacteria and eukaryotes) and forms a transcription-competent complex that can start RNA synthesis. After this, promoter clearance allows the polymerase to transition into the elongation stage, during which it moves along the DNA, unwinds the double helix ahead of it, and adds nucleotides to the growing RNA chain in the 5′ to 3′ direction. The elongation stage continues until a termination signal is encountered, at which point transcription ends, the RNA is released, and the polymerase dissociates. In the given statements, describing elongation as ending at the promoter is incorrect because elongation proceeds beyond the promoter region into the gene until termination; and saying termination occurs before transcription begins is false because termination follows the synthesis of the RNA. The promoter-recognition and polymerase-binding feature is the best tailored highlight for the initiation stage.