Which of the Following Best Describes the Lac Operon

Question

Which of the following best describes the lac operon?
A) Negatively controlled repressible operon
B) Negatively controlled inducible operon
C) Negatively controlled constitutive operon
D) Positively controlled repressible operon
E) Positively controlled inducible operon

Accepted Answer

The lac operon is a negatively controlled inducible operon, meaning that transcription is repressed in the absence of lactose and induced in the presence of lactose. The lac repressor protein binds to the operator in the absence of lactose, preventing RNA polymerase from transcribing the genes involved in lactose metabolism. When lactose is present, it binds to the repressor protein, causing a conformational change that releases it from the operator, allowing RNA polymerase to transcribe the genes.