Catabolic vs. biosynthetic operons Operon encodes absence of effect presence of Effect Catabolic Induced Substrate Repressed Substrate enzymes (derepressed Biosynthetic Product Induced Product Repressed enzymesCatabolic vs. biosynthetic operons Absence of Catabolic enzymes Biosynthetic enzymes Effect Induced Repressed Operon encodes Presence of Effect Substrate Product Product Substrate Induced (derepressed) Repressed