PSL300H1 Lecture Notes - Cell Adhesion, Glut1, Glycolipid
Document Summary
Permeability depends on molecular size, lipid solubility and charge. Polar end (hydrophilic): glycerol + phosphate + choline/serine/etc. Non-polar end (hydrophobic): normally 1 fatty acid (fa) tail is saturated, other polyunsaturated. Mechanical properties of membrane determined by lipid composition. Essential for ef cient carrier and channel protein fxn. Cholesterol stabilizes membrane & prevents diffusion of polar molecules across it. Reduced by agin & poor diet (fa sourced from food) Transmembrane (tm) channels for diffusion of selected molecules/ions. Selective transporters (carriers) of molecules across membrane. Receptors for signaling molecules (part of endocrine system) Crossing membrane 7x common: one end of peptide chain on either side. Sections of protein crossing membrane usually are helical, and outside the membrane, sections are usually beta sheets. Matrix of long carb laments that ll extracellular space (ecs, or f for uid), slowing down diffusion of molecules into cell (cell"s fur coat ) Anchored to membrane proteins (glycoproteins) or lipids (glycolipids)
