PSL300H1 Study Guide - Final Guide: Endocytosis, Fokker E.Ii, Electromagnetism
7 Jan 2017
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Background information: cell membrane, cell membrane permeability, simple diffusion, facilitated diffusion, active transport, secondary active transport, channels, voltage-gated channels, ligand-gated channels, endocytosis and exocytosis, kiss and run, full fusion. Membrane potential: na+/k+ pump, resting membrane potential (rmp) If a substance can cross the membrane by any means, the membrane is permeable to that substance. Polar molecules and ions need the help of proteins (channels or carriers) to cross. Cell membrane is not an inert bag holding the cell together. Lipid-soluble molecules and gases (small things) diffuse through readily. Water-soluble molecules cannot cross without help (polar molecules) Impermeable to organic anions (proteins, also very large) Permeability depends on molecular size, lipid solubility, and charge. It may be helpful to think of selective permeability as a white polar bear with a salmon in its mouth: Bear large cannot go through. Salmon protein cannot go through: simple diffusion.
