Which of the following terms best characterizes catabolite repression associated with the lac operon in E. coli?

Present a detailed description of the actions of the regulatory proteins in inducible and repressible enzyme systems.

(a) Describe by labeled diagram the structural components of the lac operon in E. coli.
a() State the function of the lac regulator gene.
b() State the function of fi -galactosidase in the lac system.
c() Show by diagram the manner in which lactose brings about transcription of the three structural genes of the lac operon.
d() Explain why certain mutations in the regulator gene (I -) of the lac system result in maximal synthesis of fi -galactosidase, permease, and transacetylase even in the
absence of the inducer (lactose).