BSCI 105 Lecture Notes - Lecture 11: Quorum Sensing, Signal Transduction, Cell Membrane
13 Aug 2016
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Document Summary
The cell as the fundamental unit of life. Why: unicellular organisms influence behavior of other cells. Coordination quorum sensing: multicellular organisms coordination. Signaling molecules: released in response to a stimulus, ligand interacts with a receptor, only effects cells with receptor, can be just about any type of molecule. Receptors: cell type specific, different types: Specific site: channel opens, ions flow through, ion concentrations change, ions trigger response. Each receptor binds a different ligand: protein, amino acid, fatty acid, carbohydrates, inorganic molecules. Share similar structure: no ligand bound inactive. Receptor and g-protein are not linked, but close to each other in the plasma membrane: ligand bound activated. G-protein complex changes shape gdp exchanged for gtp. Activated protein initiates signal cascade: provides specificity. Gtp hydrolyzed to gdp g-protein inactivated, signal terminated. Example: epinephrine receptors o o o blood o o o. Increased hydrolysis of glycogen and release of glucose into.
