Transcription of the structural genes in an inducible operon

Question

a occurs continuously in the cell.

b starts when the pathway's substrate is present.

c starts when the pathway's product is present.

d does not result in the production of enzymes.

e stops when the pathway's product is present.

Answer 1

b.  The structural genes are those that code for enzymes that work on a particular substrate.  In an inducible operon, transcription is turned on, or induced, when there is a need for those enzymes to be made.  The enzymes need to be made when the substrate is around.