Final answer:
Bacterial promoters under the control of transcriptional activators generally bind weakly to RNA polymerase, while those under control of transcriptional repressors bind strongly to RNA polymerase; hence, the correct answer is A. weakly; strongly.
Step-by-step explanation:
Generally, bacterial promoters that are regulated by transcriptional activators bind weakly to RNA polymerase on their own, but promoters that are regulated with transcriptional repressors bind strongly to RNA polymerase. Therefore, the correct answer to the student's question is: A. weakly; strongly.
Transcriptional activators facilitate the binding of RNA polymerase to the promoter, enhancing transcription of the gene. Conversely, transcriptional repressors impede RNA polymerase's progress, thus preventing transcription. The promoter regions in prokaryotes typically contain consensus sequences such as the -10 and -35 regions that are recognized by the σ subunit, which is important for the binding of RNA polymerase and initiation of transcription.