Lecture 11 Osmosis

Lecture 11 Osmosis - SOLUTES REDUCE WATER POTENTIAL-solutes...

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Lecture 11 Osmosis DIFFUSION - diffusion is the tendency for molecules to spread out evenly into the available space-down from its concentration gradient-if all other forces are equal - although each molecule moves randomly, diffusion of a population of molecules may exhibit a net movement in one direction molecules tend to change from a state of higher free energy to lower free energthe change of state is spontaneous OSMOSIS - DIFFUSION OF WATER ACROSS A SELECTIVELY PERMEABLE MEMBRANE - Substances diffuse down their concentration gradient, the different in connce WATER POTENTIAL - THE POTENTIAL ENERGY OF WATER MOLEcules in relation to pure water. - Water potential is determined by free (unbound)water mole - Solute mreduces water potential - Water molecules move from regon
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Unformatted text preview: SOLUTES REDUCE WATER POTENTIAL-solutes bind to water molecules, reducing the amount o MOLARITY VS. OSMOLARITY-molelcules that do not ionize in water: o molarity=osmolarity o e.g. glucose 1M=1osM-Molecules that ionize in water: o Molarity<Osmalarity o E.g. RED BLOOD CELL-cellular content is complex-both soluble and insoluble substances (matrix) in cell can reduce water potential-human red blood cell has about -0.3 osM of solute and matrix (Psi=/about .7Mpa) MEMBRANE STRUCTURE RESULTS IN SELECTIVE PERMEABILITY-a cell must exchange materials with its surroundings, a process controlled by the plasma membrane-in general hydrophobic molecules pass through membrane more easily than hydrophilic molecules...
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Lecture 11 Osmosis - SOLUTES REDUCE WATER POTENTIAL-solutes...

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