Final answer:
The -10 and -35 elements constitute a bacterial promoter. These regions are promoter consensus sequences with specific sequences recognized by the sigma factor, which then helps the core RNA polymerase to bind and initiate transcription. Core RNA polymerase, sigma factor with core RNA polymerase, and transcriptional factor TFIID do not define a promoter themselves.
Step-by-step explanation:
The student asks which of the following constitutes a bacterial promoter. The answer is option 2: the -10 and -35 elements. In bacterial cells, a promoter is a DNA sequence where the transcription machinery, including RNA polymerase, binds to initiate transcription. Specifically, the -10 and -35 regions upstream of the initiation site are known as promoter consensus sequences, with TATAAT for the -10 region and TTGACA for the -35 region. These sequences are recognized and bound by the sigma factor, which then enables the core RNA polymerase to bind to the DNA and begin transcription.
It's important to note that core RNA polymerase by itself (option 1) is not a promoter, it needs to associate with the sigma factor to initiate transcription. The sigma factor plus core RNA polymerase (option 3) comprises the holoenzyme that initiates transcription but does not constitute the promoter sequence itself. Option 4, Transcriptional factor TFIID, is not involved in bacterial transcription but is part of the eukaryotic machinery for recruiting RNA polymerase II to the promoter in eukaryotes.