BIOL 1090 Lecture Notes - Lecture 19: Cell Membrane, Signal Transduction, Liposome

• School: University of Guelph
• Department: Biology
• Course: BIOL 1090
• Professor: Jaideep Mathur

Document Summary

All membranes share common properties: ~6nm thick, stable, flexible, capable of self assembly (liposomes) Membranes have different functions in different cells and within an individual cell. Lipid movement to other leaflet is slow. Membrane proteins diffuse within the bilayer: movement of proteins is restricted, some do(cid:374)"t (cid:373)ove, rapid movement is limited by space, long range diffusion is slow, biochemical modification can greatly affect protein mobility in the membrane (signal transduction) Different membrane contain different types of lipids and proteins. Small areas of the plasma membrane enriched in certain types of lipids (cholesterol) May form functional compartment (nature/function of rafts is controversial) Lipid bilayers do not allow many compounds to pass freely. Very small molecules, uncharged (o2, co2, h2o) Down a concentration gradient (flow is downhill: diffusion through channel. Ions channels are selective, allowing only one types of ion to pass. Voltage-gated: responds to change in charge across membrane.