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The Membrane!!!! (and some transport stuff!). M . Tweedie Honors/College Biology. Made of Phospholipids. Hydrophilic “Heads” Hydrophobic “Tails” Lipids are INSOLUBLE in water!!!!!!!!!. Lipid Bilayer. “Tails” will repel water and be pushed inward to form the membrane. Water. Water.
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The Membrane!!!!(and some transport stuff!) M. Tweedie Honors/College Biology
Made of Phospholipids • Hydrophilic “Heads” • Hydrophobic “Tails” • Lipids are INSOLUBLE in water!!!!!!!!!
Lipid Bilayer • “Tails” will repel water and be pushed inward to form the membrane Water Water
Selectively Permeable You ain’t cool enough to get in here!!!!!! • Only lets certain substances in or out!!!!!!! • Just like a Doorman at a night club! Inside “Club Cell” Cell Security Why not, are we not hydrophobic enough? This is the Best Club EVERRR!
What happens to molecules that can’t get through? • If you are: • Too Big • Hydrophilic (polar/charged) • Then you need proteins to get through!! • Protein Channels • Transport Proteins
How do molecules move through? • Two Kinds of Transport: • Passive Transport – does not require energy • Molecules move from an area of High Concentration to an area of Low Concentration • Active Transport – requires energy from the cell • Molecules move from an area of Low Concentration to an area of High Concentration
Which way do the Molecules Move without energy? • Diffusion is the Rule! • From an area of high concentration to an area of low concentration • Molecules will cross the membrane from an area of high to low concentration too!