You are given a constitutive mutant, but you are not told whether it is constitutive due to a repressor mutation (i-) or an operator mutation (oc). Determine what could be added to the system that would allow you to determine the difference between the two mutants. You will add the same thing to each and indicate the results of the experiment.

Repressor molecules, as we recognize them to be proteins occur as transcription factors that may function on their binding sites within the same genome or even on a different genome.

As a result, repressor molecules behave in a trans-active manner. Operator, on the other hand, acts as a binding site mostly on the chromosome genome which can only trigger downstream genes. As a result, Operators are cis-acting.

In this scenario, if we give the system a Plasmid containing a wild-type repressor gene, the repressor molecules would only attach to the usual Operator sites.

In the 1st scenario:

The Operator is regular and normal, but I- is mutated. As a consequence, the additional extra plasmid's normal repressor molecules will stick to the operator site, causing suppression or repressed expression.

In the 2nd scenario: genome

The repressor is natural, but Oc is mutated. As a consequence, the additional extra plasmid's normal repressor molecules would not adhere to the operator region, resulting in the same Constitutive expression.