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Unformatted text preview: Cell Membranes Laws of Thermodynamics
1. Energy is neither created nor destroyed changes form 1. Everything moves from orderly to disorderly (entropy) until equal Function of Cell Membranes Protection Boundary Monitors what enters & leaves cell Cell Membranes Permeable allows everything to pass through Nonpermeable doesn't allow anything to pass through Semipermeable or selectively permeable allows certain molecules to pass through Membrane Permeability Wikipedia.com Alienryderflex.com Movement of Molecules & Energy Molecules constantly in motion try to reach equilibrium Higher temperature faster molecules move Movement of molecules concentration gradient unequal # of molecules in one area compared to another area Concentration gradient Biosci.ohiou.edu Transport across cell membrane Passive Transport --no energy required -- from higher conc to lower conc until equal Diffusion passive transport Movement of solute from an area of higher conc to an area of lower conc until equal Example of Diffusion Kentsimmons.uwinnepeg.edu passive transport Osmosis Movement of H2O from area of higher conc to area of lower conc until equal must cross cell membrane Scienceaid.co.uk amount of solute in soln determines if H2O will move from one soln to another 1. Isotonic solute conc are equal 2. Hypertonic solute conc is more 3. Hypotonic solute conc is less Tonicity Tonicity in animal cells Emc.maricopa.edu Personal.psu.edu Active Transport requires energy to move molecule from lower conc to higher conc Active Transport Biology4kids.com Cells bring materials into cell -Endocytosis and phagocytosis Cells move materials out of cell -Exocytosis Emc.maricopa.edu ...
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