Molecular Basis Of Inheritance Question 122

Question: Which enzymes will be produced in a cell in which there is a nonsense mutation in the lac Y gene?

Options:

A) Lactose Permease

B) Transacetylase

C) Lactose permease and transcetylase

D) $ \beta $ -galactosidase

Show Answer

Answer:

Correct Answer: D

Solution:

[d] A non-sense mutation is the one which stops polypeptide synthesis due to formation of a terminating or non-sense codon.

e.g.

ATT(UAA), ATC (UAG), ACT(UGA).

The lactose or lac operon of Esherichia coli contains structural genes (z, y, a).

If Y codes for termination of polypeptide chain then only the product of ‘z’ gene transcribe to form $ \beta $ galactosidase.