In the $lac$ operon,which gene is responsible for coding the repressor protein?

During $DNA$ transcription,$mRNA$ is usually single-stranded. However,sometimes an $RNA$ molecule is produced that is complementary to the $mRNA$. This is called ...... and its function is to ...... .

In the Operon concept,the regulator gene regulates chemical reactions in the cell by:

Who proposed the operon model for the first time?

In an $E. coli$ strain,the $i$ gene gets mutated such that its product cannot bind the inducer molecule. If the growth medium is provided with lactose,what will be the outcome?

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