Functioning of structural genes is controlled by
Operator
Promoter
Ligase
Regulatory gene
Jacob and Monad studied lactose metabolism in E. coli and proposed operon concept, which is applicable for
$A$ : Operator gene is functional when it is not blocked by repressor.
$R$ : Regulator gene produces active protein only which acts on operon system in $E$.coli
E.coli cells with a mutated $Z$ gene of the lac operon cannot grow in medium containing only lactose as the source energy because
In lac operon system lac gene -$I $ codes for
In Escherichia coli, lac operon is induced by