Question

How are the two sigma factors σ70 and σ32 in E. coli different from each other?

a) They differ in size
b) They bind to different promoters
c) They regulate different metabolic pathways
d) All of the above

Answer 1

The two sigma factors σ70 and σ32 in E. coli differ in size, bind to different promoters, and regulate different metabolic pathways.

Step-by-step explanation:

The two sigma factors σ70 and σ32 in E. coli differ from each other in several ways:

1. They differ in size - σ70 has a molecular weight of about 70 kDa, while σ32 has a molecular weight of about 32 kDa.
2. They bind to different promoters - σ70 is the primary sigma factor that binds to the promoters of most genes, while σ32 specifically binds to heat shock promoters.
3. They regulate different metabolic pathways - σ70 plays a general role in transcription initiation, while σ32 is involved in the response to heat shock and stress conditions.

Therefore, the correct answer is d) All of the above.