Answer
If the cells produced normal tryptophan repressor protein from a second, normal gene in 1 and 2 the regulation of the tryptophan biosynthesis enzymes would be restored. However, the expression of the normal protein would not matter in situation 3 because the tryptophan operator would be occupied by the mutant protein even if tryptophan is present
Work Step by Step
The tryptophan operator would be occupied by the mutant protein.
