HNRS 1007 Lecture Notes - Lecture 5: Phagocytosis, Pinocytosis, Solution
Document Summary
Phospholipid are most abundant lipid in plasma membrane. Exhibits selective permeability (only certain substances may cross) The fluid mosaic model= membrane has fluid structure with mosaic of proteins embedded within. As temp. cools, membrane becomes less fluid. Temp. response depends on type of lipids. Ability to change lipid compositions in response to temp. where organism lives. Cholesterol is good for you in the right amount: has diff. effects on membrane fluidity at diff. temp, warm temp. , cholesterol restrains movement of phospholipids, at cool temp. , maintains fluidity by preventing tight packing. Very few things cross membrane by themselves: hydrophobic molecules, some water, never: In facilitated diffusion--- transport proteins speed passive movement of molecules across membrane: channel proteins. Provide corridors allowing specific molecule/ion to cross membrane. Undergo subtle change in shape that translocates the solute-binding site across the membrane: solutes move from high to low concentration, see slide 10.
