Gene Regulation: Operons and Epigenetics · Zoology

The lac operon is an example of a:

  1. Repressible operon
  2. Constitutive operon
  3. Inducible operon system
  4. Eukaryotic operon
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Correct answer: Inducible operon system

The lac operon is an inducible system: it is normally repressed by the lac repressor and switched on only when lactose (converted to allolactose) is present. This allows the bacterium to express the lactose-metabolizing enzymes only when the substrate is available.

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