Q. The lac operon consists of
A) Four regulatory genes only
B) One regulatory gene and three structural genes
C) Two regulatory genes and two structural genes
D) Three regulatory genes and three structural genes
Explanation
[Solution from source] The lac operon has one regulatory gene (i, coding the repressor) and three structural genes: z (β-galactosidase), y (permease) and a (transacetylase), along with promoter and operator sites. The promoter and operator are DNA sites, not genes, so it does not have two or three regulatory genes. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.