Question

Are Open promoters active or inactive? Where are they located?

1) Active and located upstream of the transcription start site
2) Inactive and located downstream of the transcription start site
3) Active and located downstream of the transcription start site
4) Inactive and located upstream of the transcription start site

Answer 1

Open promoters are active regions where transcription machinery binds to begin transcription, usually located upstream of the transcription start site. They play a crucial role in the regulation and initiation of gene transcription.

Step-by-step explanation:

Open promoters refer to the regions of DNA that are active for initiating transcription. These promoters are typically located upstream of the transcription start site. The promoter is a critical DNA sequence where the transcription machinery, including RNA polymerase, binds to initiate transcription. In prokaryotic cells, consensus sequences such as the -10 (TATAAT) and -35 (TTGACA) regions help in positioning the RNA polymerase correctly. These regions are upstream and referred to as the 5' upstream untranslated region. In contrast, eukaryotic promoters may be larger and more complex but also contain a TATA box region. Promoters are essential because their specific sequences determine the frequency at which the corresponding gene is transcribed.