Chapter 7 Pgs 125 129 131 136 138 139 What is the composition of the membrane 2 layers of phospholipids Amphipathic Properties Hydrophilic and Hydrophobic Proteins Globular Proteins Hydrophilic Outside Hydrophobic inside Cholesterols Depends on Temperature Sandwich Model was wrong Used Freeze Fracture Preparation to prove Cells frozen in block of ice Fluid Mosaic Model early 1970 s Fluid Lipids Mosaic Proteins o Integral o Peripheral Examples of Membrane Proteins Transport Enzymatic Activity Signal Transduction Cell Cell recognition Intercellular joining Attachment to the cytoskeleton and extra cellular matrix ECM Why is selective permeability important What is Transported in out of cells How is it transported Hydrophobic or nonpolar O2 CO2 Steroids Hydrophilic polar or charged H2O proteins saccharides ions Diffusion Tendency for molecules to spread out Down Concentration gradient If across a biological membrane via passive transport no energy required Lab examples Potassium Permanganate or starch amylase Osmosis Movement from High Concentration to Low Concentration DIFFUSION OF WATER Via passive transport no energy required Across a selectively permeable membrane RELATED TERMS Tonicity Property of a solution in reference to a particular membrane Isotonic No net movement solutions have equal solute Hypertonic solution has higher solute compared to other Hypotonic solution has lover solute compared to other