BIOL 031 Lecture Notes - Lecture 2: Conformational Change, Dynamic Equilibrium, Facilitated Diffusion
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Explain what happens with regard to cell volume when it is placed in hypertonic, isotonic, and hypotonic solutions is greater (osmolarity is greater in solution) Hypertonic: cell shrinks; fluid moves out of cell, solute concentration in solution. Isotonic: no change in cell volume; flux occurs in dynamic equilibrium. Hypotonic: cell swells; fluid moves into the cell, solute concentration in cell is. Describe how proteins involved with mediated transport systems move molecules from greater (osmolarity is greater in the cell) one side of the cell membrane to another. Some substances cannot move via simple diffusion or channel diffusion either. Uses energy in active transport or in facilitated diffusion due to an opposing charge or too great of a size to fit through the channel. Facilitated diffusion (no energy required): proteins embedded within the membrane; the transported substance must first bind to a specific site on a transporter, a site exposed to the solute on one surface of the membrane.