Question

Identify the mismatched pair of the genes related to the lac operon and the respective proteins they code for.

• A. LacY- β-galactosidase
• B. LacA- β-galactoside transacetylase
• C. LacZ- lactose permease
• D. All are correct

Answer 1

Answer: (A), (C)

The correct options are
A LacY- β-galactosidase
C LacZ- lactose permease

The three major enzymes involved in the digestion of lactose in the human gut are β-galactosidase, β-galactoside transacetylase and lactose permease. These are produced by transcription of three structural genes of the lac operon of E.coli. Of these, the gene lacZ codes for the enzyme β-galactosidase, lacY codes for lactose permease and lacA codes for β-galactoside transacetylase.