An $E. coli$ cell with a mutated $z$ gene of the $lac$ operon cannot grow in a medium containing only lactose as the source of energy because:

Which of the following is true for a repressible operon?

Human gene expression is regulated when steroid molecules bind to:

Which gene produces the lactose repressor?

Which of the following is not a component of the $Operon$ model?

Consider the following statements of gene regulation and select the correct statements $:$
$(A)$ Expression of genes is regulated by metabolic,physiological,or environmental conditions.
$(B)$ Galactose can act as an inducer for the lac operon.
$(C)$ The operator region is adjacent to the promoter elements in most operons.
$(D)$ In the lac operon,lactose is transported into the cell through the action of permease.
$(E)$ Regulation of the lac operon by a repressor is referred to as positive regulation.