BIO 218 Chapter 18: Bio 218 Winter 2015
7 Aug 2016
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Inducible: resting state is off, can be induced (turned on) ex. Repressible: resting state is on, can be repressed (turned off) ex co-repressors: trp. How does positive control differ for an inducible vs a repressible system. How does negative control differ for an inducible vs a repressible system. Operon is a group of genes that work under the same promoter and it is regulated by positive or negative repression or induction. When lactose is present, the lacgenes are expressed because allolactose binds to the lac repressor protein and keeps it from binding to the lac operator. Lac i = repressor (positive negative and super repressed) Lac o = operator (positive, negative and constitutive) Lac z = beta galactosidase = cleaves lactose into glucose and galactose. Lac y = beta galactosidase permease = pumps lactose into cell. I+ = can act on cis or trans. Is = super repressible (oc is dominant over this )
