01:119:115 Lecture Notes - Lecture 12: Trp Operon, Genomic Imprinting, Operon
15 Mar 2016
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Review exam ii friday nov 8 4-5:30 hickman 138. The trp operon controls the 5 genes that code for 3 enzymes needed to produce trptophan. By default the trp operon is on and genes for tryptophan synthesis are transcribed. The repressor is active only in the presence of its corepressor (tryptophan) 18. 3b. The lac operon contains genes that code for enzymes used in the hydrolusis and metabolism of lactose. Lactose is a disaccharide (glucose + galactose); it"s the sugar in milk. Hydrolysis of lactose into glucose and galactose is done by enzyme b-galactosidase. B-galactosidase is controlled by gene lacz which is part of lacoperon along with 2 other genes. By itself, laz repressor is acire and sqitches lac operon off . A molecule called the inducer inactivates the repressor to turn the lac operon on . Inducible enzymes usually function in catabolic pathways; their synthesis is induced by a chemical signal.
