01:119:115 Lecture Notes - Lecture 16: Lac Operon, Lactose Permease, Rna Splicing
24 Nov 2016
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Lecture 16 - gene regulation: regulation of prokaryotic genes - intro. Only a certain subset f genes are used at any given time. Constitutive genes (housekeeping genes) proteins that are always needed + constantly. If every cell in your body has the same genome, why are all of your cells not identical? transcribed. Other genes are only transcribed when needed. Ex: adrenaline when you"re scared: lac operon model: basic concepts. 3 genes for lactose metabolism in e. coli: Lac y - lactose permease - brings lactose into cell. Lac z - -galactosidease ( -gal) - hydrolyzes lactose glucose and galactose. Lac a - galactoside transacetylase - aids in lactose metabolism. If no lactose - e. coli cell does not make these enzymes. If lactose is present - enzymes are made. Operon = a group of genes controlled by a single regulatory signal controlled by an operator. Operator: short stretch of dna acts as a switch .
