BIL 150 Chapter Notes - Chapter 7: Fluid Mosaic Model, Lipid Bilayer, Membrane Transport Protein
28 Apr 2016
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Selectively permeable: let"s some substances cross it more easily than others. Fluid mosaic model of membrane is a mosaic of protein molecules bobbing in fluid layer of phospholipids. Phospholipids move laterally very quickly all the time (they drift) 7: proteins are larger so they do move but slower. Membranes fluid until temperature decreases and membrane solidifies. Phospholipids form main fabric of membrane but proteins determine most of functions. Two kids of membrane proteins: integral proteins. Penetrate hydrophobic interior of lipid bilayer: peripheral proteins. Cells recognize other cells by binding to molecules (often containing carbs) on membrane surface. Membrane carbs short and some covalently bonded to lipids glycolipids: most covalently bonded to proteins though glycoproteins. Nonpolar molecules are hydrophobic and can dissolve in lipid bilayer and cross easily. Hydrophobic interior impedes passage of ions and polar molecules (cross slowly: charged atom even more unlikely to penetrate hydrophobic interior.
