Q. Which enzymes will be produced in a cell in which these is a nonsense mutation in the lac Y gene ?
(a) Lactose permease
(b) Transacetylase
(c) Lactose permease and transacetylase
(d) β – galactosidase
Solution :
Correct option : D A nonsense mutation is the type of mutation in which a sense codon that corresponds to one of the twenty amino acids specified by the genetic code is changed to a chain-terminating codon. A nonsense mutation in the lacY gene will make it produce a non-functional permease. Also, the stop codon will be added after the lac Z gene and hence, beta-galactosidase will be produced. Therefore, neither permease nor transacetylase will be produced, and only beta-galactosidase will be produced.