Final answer:
The lac operon can have two types of constitutive mutations — lacI- and lacOc mutations. LacI- mutations occur in the lacI gene, leading to the production of a non-functional repressor protein. LacOc mutations occur in the operator region and weaken the binding of the repressor. These mutations result in the lac operon being constitutively active.
Step-by-step explanation:
Two types of constitutive mutations in the lac operon are lacI- and lacOc mutations. The lacI- mutation occurs in the lacI gene, which encodes the repressor protein. This mutation leads to the production of a non-functional repressor, which fails to bind to the operator region and represses the lac operon. As a result, the lac operon is constitutively active, meaning it is always transcribed, even in the absence of lactose. The lacOc mutation occurs in the operator region and leads to a change in the binding site for the repressor. This mutation weakens the binding of the repressor, allowing transcription of the lac operon to occur even in the presence of the repressor. Therefore, the lac operon is also constitutive in this case.