BIOLOGY 1A Lecture Notes - Lecture 5: Lipid Bilayer, Phospholipid, Hydrophile
Document Summary
Lecture #5: overview: life at the edge, the plasma membrane is the boundary that separates the living cell from its surroundings, the plasma membrane exhibits selective permeability, allowing some substance to cross it more easily than others. More bent tails means the less well they pack together in the bilayer so the more fluid the bilayer. Freeze-fracture experiments: freeze-fracture studies of the plasma membrane supported the fluid mosaic model, freeze-fracture is a specialized preparation technique that splits a membrane along the middle of the phospholipid bilayer. In low temperature when chains are packing together tightly, break them apart to make more fluid. At higher temperature when chains of lipid tails are farther apart, help to give cohesion. Membrane buffer, help keep a constant fluidity: experiment: are membranes fluid, take two different cells and form hybrid cells with plasma membranes. Mixed proteins after an hour: suggested the fluid mosaic model was the way to explain behavior of plasma membranes.
