Do prokaryotic cells have promoters for transcription initiation?

• A. Yes
• B. No
• C. Only in certain conditions
• D. They use RNA templates

Answer: (A)

Promoters are DNA sequences that tell RNA polymerase where to start transcription. In prokaryotes, the RNA polymerase holoenzyme (with a sigma factor) binds to a promoter located upstream of the gene, and bacterial promoters often contain recognizable motifs around the -35 and -10 regions that help position the enzyme and initiate RNA synthesis. This means prokaryotic cells do have promoters for transcription initiation. While transcription can be regulated by conditions and regulatory proteins, the promoter itself is a DNA sequence present to begin transcription; it isn’t something that only appears under certain circumstances. Also, transcription uses DNA as the template to synthesize RNA, not RNA templates.