Question

In Lac operon if a mutation occurs in the middle gene of the structural genes then

• A. $\beta$ - galactosidase will not be synthesised
• B. Permease will not be synthesised
• C. Transacetylase will not be synthesized
• D. Lactose digestion will be rapid

Answer 1

Answer: (B)

Permease will not be synthesised

Lac operon is an operon which is involved in the regulation of lactose metabolism in several enteric bacteria including Escherichia coli. It is an inducible operon. It contains promotor, operator, three structural genes and terminator. the three structural genes are namely, lacZ, lacY and lacA. LacZ gene encodes for β-galactosidase, lacY encodes for β-galactoside permease and lacA encodes for β-galactoside transacetylase. Hence if mutation occurs in the middle gene of the structural genes then permease will not be synthesized. Thus the correct answer is option B.