BIOLOGY 2A03 Lecture Notes - Lecture 20: Quorum Sensing, Allosteric Regulation, Gene Expression
12 Dec 2018
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What we will cover: differential gene expression, the operon lac genes, global gene regulation, post-initiation control of gene expression, quorum sensing, two-component regulatory systems, chemotaxis. Activity of enzyme may be altered: as a result of binding of effector molecule (inhibition or activation) known as allosteric regulation, substrate no longer binds more strongly, covalent modification may also alter enzyme conformations, altering activity. Lactose: milk contains 2-8% lactose, disaccharide of galactose and glucose joined by b-1 4 glycosidic linkage. Individuals consuming dairy products may experience lactose intolerance . deficiency of lactase (b-galactosidase enzyme) The operon: operon = transcription unit with a series of structural genes and their transcriptional regulatory elements, the lac operon is the classic example. Includes an operator region where regulatory protein bind. The lac operon is turned on (induced) when needed. Global gene regulation: how does a single environmental stimulus control multiple operons, regulons are genes that are coordinated to respond the same regulatory systems.
