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Unformatted text preview: permeability will be, either by facilitating diffusion or transporting molecules, passively or actively. Key Concept 4: Passive transport of molecules across the cell membrane is achieved by facilitated diffusion, using channel or carrier proteins that selectively allow solutes to move down a concentration gradient. Key Concept 5: Active transport requires energy to move solutes against a concentration or electrochemical gradient. Key Concept 6: Uniport transporters move individual solutes independently, while symport and antiport transporters depend on the cotransport of a coupled solute either in the same or opposite direction. Key Concept 7: Cells can take in bulk solutes through endocytic mechanisms, such as phagocytosis, pinocytosis, and receptor-mediated endocytosis. Key Concept 8: Cells export bulk materials through the plasma membrane by the process of eexocytosis....
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- Fall '07