PHGY 214 Study Guide - Midterm Guide: Membrane Transport Protein, Facilitated Diffusion, Active Transport
30 Nov 2015
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Things move down their concentration or electrical gradient. Water soluble ( ions, sugars, amino acids): cross via carrier pump or channel. Move against gradient by hydrolyzing atp (overcomes energy barrier) Atp being used right then and there. Na+/k+ atpase 3na+ out, 2 k+ in. Carries: coupling movement of one solute down its gradient to another moving against its gradient. Often coupled with na+ gradient (maintained by atpase) Selective (ions selected by binding to pore amino acid very quickly then it is let go) Open by binding transmitters (glutamate, gaba, acetylcholine) Ttx & procaine (block voltage gated na+ channels) Conus toxin (blocks voltage gate ca2+ channels) Membrane potential (vm or em): potential difference in the distribution of positive and negative charges across the membrane. All cells at rest between -5 and -90mv. Neurons at rest between -50 and -75mv (-60mv) **resting permeability due to the number of open, passive channels.
