Question

Given below are two statements :
Statement I: In the lac operon, the z gene codes for beta-galactosidase which is primarily responsible for the hydrolysis of lactose into galactose and glucose.
Statement II: In addition to lactose, glucose or galactose can also induce lac operon.
In the light of the above statements, choose the correct answer from the options given below :

• A. Statement I is true but Statement II is false
• B. Statement I is false but Statement II is true
• C. Both Statement I and Statement II are true
• D. Both Statement I and Statement II are false

Answer 1

The Correct Option is A

Statement I: The z gene in the lac operon encodes β-galactosidase, an enzyme that breaks down lactose into galactose and glucose. This statement is correct.
Statement II: Lactose (or its isomer, allolactose) induces the lac operon. Glucose, conversely, represses it, a process known as catabolite repression, even when lactose is present. Galactose does not directly induce the lac operon; the induction is dependent on lactose. Consequently, statement II is incorrect.