Final answer:
The effect of temperature on the dissociation of RNAP holoenzyme from the promoter sequence is best explained by the transition from closed to open promoter complex that readily happens at higher temperatures, causing DNA melting. The open promoter complex is most stable at 37 deg and the least stable at 15 deg.
Step-by-step explanation:
The effect of temperature on the dissociation of RNAP holoenzyme from the promoter sequence is best explained by option C: Transition from closed to open promoter complex happens readily at higher temperatures (DNA melting); open promoter complex is most stable at 37 deg and the least stable at 15 deg.
At higher temperatures, the DNA strands of the promoter sequence undergo DNA melting, which facilitates the transition from the closed promoter complex to the open promoter complex. The open promoter complex is most stable at 37 degrees, making it easier for the RNAP holoenzyme to dissociate and initiate transcription. On the other hand, at 15 degrees, the open promoter complex is not formed due to the lack of DNA melting, resulting in the closed promoter complex being the most stable and having a longer half-life.