Question

E. coli has 7 different sigma subunits recognizing a different promoter sequence. What do Sigma 70 and 32 do?

a) Initiate transcription in heat shock response
b) Initiate transcription in housekeeping genes
c) Enhance translation efficiency
d) Inhibit translation in stress conditions

Answer 1

Sigma 70 initiates transcription in housekeeping genes, while Sigma 32 initiates transcription in the heat shock response in E. coli.

Step-by-step explanation:

Sigma 70 and Sigma 32 are both subunits of the E. coli RNA polymerase.

1. Sigma 70: Initiates transcription in housekeeping genes. It recognizes the -10 and -35 regions of the promoter sequence, which are specific to these genes.
2. Sigma 32: Initiates transcription in the heat shock response. It recognizes the promoter sequence specific to genes involved in the stress response.

Therefore, the correct answer is b) Initiate transcription in housekeeping genes and a) Initiate transcription in heat shock response.