According to the operon model, for the synthesis of an inducible enzyme to occur, the...?

A. end product must not be in excess


B. substrate must bind to the enzyme


C. repressor must bind to the operator


D. repressor must not be synthesized


E. substrate must bind to the repressor

According to the operon model, for the synthesis of an inducible enzyme to occur, the...?
E. Lac operon: If lactose is absent from a cell the enzymes will not be made. If the sugar enters the cell, the operon will be switched on and produce the enzymes needed to digest the lactose.


Lactose metabolism in E. coli is programmed by the lac operon which has three structural genes. lac.Z codes for B-glactosidase which hydrolyzes lactose.


lac. Y codes for permease, a membrane protein that transports lactose into the cell, and lac A codes for transacetylase, an enzyme that has no known action in lactose metabolism. Lactose acts as an inducer to turn on the operon.