Question

Suppose an operon has the following characteristics: (1) The operon codes for structural proteins that convert compound Qto compound B. (2) The operon is controlied by a constitutively expressed regulatory gene called reg. (3) In wild-type individuals, the operon is transcribed in the absence of compound B but not in the presence of compound B. (4) in reg mutants, the operon is constitutively transcribed. Is this operon inducible or repressible? Why? O It is inducible because wild-type transcription does not occur in the presence of compound B. O t is inducible because the operator in reg mutants can still bind to compound B O It cannot be determined because the number of structural genes is unknown. O t is repressible because reg transcription only occurs in the presence of compound B O t is repressible because wild-type transcription is repressed in the presence of compound B

Answer 1

Answer: It is repressible because wild-type transcription is repressed in the presence of Compound B

Explanation:

An operon is a segment of DNA containing adjacent genes including structural genes, an operator gene, and a regulatory gene. In other words you can say it is the functional unit of transcription and gene regulations.

There are 3 types of operons

1) inducible operon- this system is a regulated unit of genetic material which is switched on in response to the presence of a chemical. Means that transcription is turned on when a specific molecule is present.

2) Repressible Operon: in this system, transcription stops when the repressor gene product is activated and the sufficient amounts of the gene product inhibit further transcription.

The third is Constitutive Operon: in this case, the amount of gene product is constant.