<prompt> Number of structural genes in Lac operon is3456  <response>: The structural gene for b-galactosidase lacZ is clustered with the genes responsible for the permeation of lactose into the cell lacY and for thiogalactoside transacetylase lacA. The structural genes for these three enzymes, along with the lac promoter and lac operator a regulatory region, are physically associated to constitute the lac operonRef: Harper 27e, page: 430 