Distinguish between structural gene, regulatory gene and operator gene.

Explanation

Structure of the operon: Each operon is a unit of gene expression and regulation and consists of one or more structural genes and an adjacent operator gene that controls transcriptional activity of the structural gene.
i. The structural gene codes for proteins, rRNA and tRNA required by the cell.
ii. Promoters are the signal sequences in DNA that initiate RNA synthesis. RNA polymerase binds to the promoter prior to the initiation of transcription.
iii. The operators are present between the promoters and structural genes. The repressor protein binds to the operator region of the operon.