Final answer:
In prokaryotic transcription, at least two proteins are involved: RNA polymerase and a sigma factor. Option 2 is correct.
Step-by-step explanation:
Prokaryotic Transcription
Prokaryotic transcription requires several components, including RNA polymerase and sigma factors. RNA polymerase is the enzyme responsible for synthesizing RNA from a DNA template. The initiation of transcription in prokaryotes involves the association of RNA polymerase with a sigma factor that enables the enzyme to recognize and bind to specific promoter regions of the DNA.
The combination of RNA polymerase and a sigma factor is necessary for the initiation of transcription. Therefore, the answer to the question, 'How many proteins are involved in prokaryotic transcription?' is at least two: RNA polymerase and a sigma factor.
The process of transcription initiation begins with the formation of this complex, which then binds to the promoter region, located 3'5' upstream of the transcription start site. The transcription process concludes with the termination phase, where the synthesis of RNA ceases and the RNA polymerase detaches from the DNA template.
Transcription in prokaryotes is typically simpler than in eukaryotes, as they use a single RNA polymerase and do not have to modify RNA post-transcriptionally since they lack a membrane-enclosed nucleus.
In summary, prokaryotic transcription is a vital process for gene expression where transcription is initiated by the RNA polymerase-sigma factor complex binding to specific promoter regions, followed by elongation of the RNA chain and eventually termination. Promoters and sigma factors are key to regulating which genes are transcribed and when.
Together, they initiate transcription by binding to the promoter region, followed by elongation and termination of the RNA transcript. Promoters and sigma factors are crucial in gene expression regulation.