In the $lac$ operon,the $lac$ $mRNA$:

An organism is able to survive on a culture medium containing nutrient $A$ through an enzyme-catalyzed process: $A \xrightarrow{X} B \xrightarrow{Y} C$. $A$ mutant organism fails to survive on this medium. However,it grows when nutrient $B$ is added to the medium. Which gene of this mutant is defective?

The $lac$ operon is a part of which of the following?

Which enzyme will be produced in a cell if there is a nonsense mutation in the lac $Y$ gene?

What is the structural gene equivalent to?

The equivalent of a structural gene is