Question

In regulation of gene expression in prokaryotes
I. Lactose acts as the suppressor for gene expression.
II. Tryptophan acts as the inducer for gene expression.
III. Regulator gene is the one that produces the repressor molecule.
Which of the statements given above are correct?

• A. Only I
• B. Only II
• C. Only III
• D. II and I
• E. II and III

Answer 1

The correct option is C Only III

In the regulation of gene expression in prokaryotes, regulator gene is the one that codes for a repressor protein molecule.
Tryptophan does not act as an inducer of gene expression since the presence of tryptophan activates the repressor protein, which then binds to the operator region of the trp operon and prevents gene expression.
Lactose acts as an inducer of the lac operon and induces gene expression.