Question

Which is an arrangement of genes consisting of an operator, a promoter, and a repressor?

1) RNA polymerase

2)anticodon

3)codon

4)operon

Answer 1

The correct answer is 4)operon

Step-by-step explanation:

An operon is a set of genes that contains its own promoter, operator and repressor. All genes present in an operon are expressed in a single unit which has a single promoter. They are commonly found in prokaryotes.

An operon consist some structural gene which is transcribed by RNA polymerase when polymerase binds to promoter region for example lac operon have three structural gene Z, Y, and A.

The operator overlaps the promoter region and binds with the regulatory proteins so it regulates the transcription of the operon. Repressor gene synthesis repressor protein which binds to operator and blocks transcription of structural genes.

Answer 2

The correct answer is option 4. An operon is an arrangement of genes consisting of an operator, a promoter, and a repressor. It is a functioning unit of DNA which contains cluster of genes controlled only by a single promoter.