In $lac$ operon,the gene '$i$' codes for repressor protein,the letter '$i$' indicates . . . . . . .

The functioning of structural genes is controlled by:

Write an explanatory note on gene expression.

Select two correct statements from the four $(a-d)$ given below regarding the $lac$ operon.
$(A)$ Glucose or galactose may bind with the repressor gene and induce inactivity.
$(B)$ In the absence of lactose,the repressor binds with the operator region.
$(C)$ The $z$-gene codes for permease.
$(D)$ This was elucidated by Francois Jacob and Jacques Monod.
Which of the following are the correct statements?

What are promoter,operator,and structural genes?

In the $lac$ operon,which enzyme$(s)$ will be produced in the cell if there is a nonsense mutation in the $lac$ $y$ gene?