The more the concentration of unsaturated hydrocarbons in the phospholipid tails, the longer the membrane stays fluid (Because of kinks in the tails, they cannot pack closely).Membranes remain fluid when temperature decreases - up to a certain critical temperature, after which they solidify.Some proteins are held in place by the cytoskeleton.The embedded proteins or surface proteins also drift.The phospholipids of membranes are constantly drifting - moving laterally.(Protein + Oligosaccharide = Glycoprotein) Cholesterol (Oligosaccharide added in the Golgi body) (Part of cytoskeleton) The fluid mosaic model Membranes have the consistency of cooking oil! Proteins are found in the layer – the hydrophobic region of proteins are found in the center of the bi-layer, with the hydrophilic regions protruding on both sides.Phospholipids are amphipathic, so the center of the bi-layer is hydrophobic and the outsides are hydrophilic.Basic fabric of membranes is a phospholipid bi-layer.Hydrophobic region of protein Hydrophilic regions of protein Membrane Structure Membrane Structure and Function Chapter 7

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