Question

Which of the following represents the correct sequence of genes of a lac operon system?

• A. Promoter gene, repressor, structural genes
• B. Repressor, structural genes, operator gene
• C. Promoter gene, operator gene, structural genes
• D. Structural genes, promoter gene, operator gene

Answer 1

The correct option is C Promoter gene, operator gene, structural genes

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.