Question

According to the lac operon model proposed by Jacob and Monod, what is predicted to occur if the operator is removed from the operon?

Only lacY would be transcribed.
The lac operon would be transcribed constitutively.
Galactosidase permease would be produced, but would be incapable of transporting lactose.
Only lacZ would be transcribed.

Answer 1

The right answer is The lac operon would be transcribed constitutively.

An operator is a nucleic acid segment to which a regulatory protein that modulates downstream gene expression is bound. it can either stimulate or inhibit the production of the gene product thus controlled.

If the operator is absent, there will be no more regulation of the operon, so the transcription of the operon will not be regulated, and the synthesis will be continuous and constitutive.