Question

The -10 and -35 regions of prokaryotic promoters are called consensus sequences because they __________.

a) exhibit variability among different species
b) are identical across different genes
c) are recognized by RNA polymerase
d) are the same in all prokaryotic organisms

Answer 1

The -10 and -35 regions of prokaryotic promoters are called consensus sequences because they are regions with similar sequences across various bacterial species, which are recognized by the sigma factor of RNA polymerase. Hence, the correct answer is option (c).

Step-by-step explanation:

The -10 and -35 regions of prokaryotic promoters are called consensus sequences because they are similar across all promoters and across various bacterial species. These sequences are vital for the initiation of transcription as they are recognized and bound by the sigma (σ) factor of RNA polymerase. The TATAAT sequence, known as the -10 region, and the TTGACA sequence at the -35 region, are conserved among prokaryotes.

Despite some variations among different species, these consensus sequences facilitate the binding of transcription machinery and the unwinding of the DNA template, essential for starting transcription.