Most structural genes of bacteria are grouped together and transcribed from a single ; immediately following this sequence is the that interacts with a regulatory protein to affect transcription of the genes.

Options for the question are not given. They are as follows:

A) regulon; promoter

B) ribosome; Shine‐Delgarno sequence

C) promoter; operator

D) promoter; regulon

E) Shine‐Delgarno sequence; operator

C) promoter; operator

Explanation:

In bacteria most structural genes are grouped under the same promoter in an arrangement known as operon. RNA Polymerase binds to this promoter and transcribes all the genes in the operon.

After promoter, an operator sequence is present in operon. It can cause the transcription to turn on or off. For example: if a repressor binds to the operator, RNA Polymerase will not be able to move ahead as it will be blocked by the repressor. As a result translation will not occur. Hence, option C is correct.

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