BISC 160 Chapter Notes - Chapter 7: Intermembrane Space, Extracellular Fluid, Protein Kinase
8 Sep 2013
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Document Summary
Tumors reproduce uncontrollably because of self- stimulation: paracrine: signals diffuse to and affect nearby cells. Neurotransmitter made by one nerve cell that diffuses to an adjacent cell and stimulates it. A signal transduction pathway involves a signal, a receptor, and responses: in a multicellular organism, all cells may receive chemical signals that are circulated in the blood. Signal: a cell must perceive and quickly respond to environmental signal. Responder: the charged phosphate group that was attached to the envz causes its cytoplasmic domain to change shape again. It now binds to a second protein, ompr, and transfers the protein to it. Receptors have specific binding sites for their signals: a molecule that binds to a receptor site on another molecule to change its shape is called a ligand. Receptors can be classified by location and function: cytoplasmic receptors. Small or nonpolar ligands can diffuse across the nonpolar phospholipid bilayer. Large or polar ligands cannot cross the lipid bilayer.
