plas Amphipathic Spontaneously form lipid bilayers
12 Lipids ➢ Amphipathic ➢ Spontaneously form lipid bilayers
Lipids are amphipathic hydrophilic Pola H2N(CH) head ydrophilic) PHOSPHATE 0=P-0 hydrophobic tails
13 Lipids are amphipathic Polar
Lipids spontaneously form structures A lipid water I nm A lipid bilayer is a stable, low energy structure Self sealing structure/eliminate free edge What drives this structured association? Exclusion of lipids from Water. not lipid association
14 Lipids spontaneously form structures A lipid bilayer is a stable, low energy structure Self sealing structure/eliminate free edge What drives this structured association? Exclusion of Lipids from Water… not lipid association
Lipid bilayers will form closed structures ENERGETICALLY UNFAVORED Compartments planar phospholipid bilal with edges exposed to water Self seal if disrupted sealed compartment formed by phospholipid bilayer ENERGETICALLY FAVORED
15 Lipid bilayers will form closed structures ➢ Compartments ➢ Self seal if disrupted
Lipids are effective barriers to some compounds SMALL HYDROPHOBIC CO2 MOLECULESN2 Hydrophobic compounds benzene can reach equilibrium UNCHARGED H20 POLAR glycerol quickIy MOLECULESethanol >"Unfavored"compounds UNCHARGED glucose can be brought across by MoLECuLes nucleotides. transport proteins H Na IONS HCO3, K Ca2+ Cl eea Tor Transport Mechanisms synthetic lipid bilay
16 Lipids are effective barriers to some compounds ➢ Hydrophobic compounds can reach equilibrium quickly ➢ “Unfavored” compounds can be brought across by transport proteins Need for …..Transport Mechanisms