The lac operon contains three genes: lacz, lacy, and laca for β‑galactosidase, galactoside permease, and thiogalactoside transacetylase, respectively. the operon also contains a promoter site and an operator site. the regulatory gene includes the i gene for the lac repressor protein and a promoter for that gene. this d n a sample contains two regions, the regulatory gene region and the lac operon region. the regulatory gene regions contains p subscript i and the lac i gene. the lac operon region contains a promoter site, an operator site, and the lac genes z, y, and a, in that order. the lac operon undergoes negative regulation. in the normal condition, the lac repressor protein is active. allolactose, an isomer of lactose, is the signal molecule that binds to the lac repressor. determine which events will increase the concentration of lac gene products and which will decrease the concentration of lac gene products.