Question

Select the correct order of the components of Lac operon in E. coli.

• A. Pi → i → P → O → LacZ → LacY → LacA
• B. Pi → i → O → P → LacZ → LacY → LacA
• C. Pi → i → P → O → LacZ → LacA → LacY
• D. Pi → i → O → p → LacZ → LacA → LacY

Answer 1

The correct option is A

Pi → i → P → O → LacZ → LacY → LacA

The Lac operon of E. coli consists of a promoter gene, operator gene and three structural genes, all of which work together to digest lactose. There is also a regulator gene which is usually present outside the operon, but is essential, as it codes for the repressor protein.