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Diffusion/Osmosis
| Term | Definition |
|---|---|
| Diffusion | he movement of molecules from an area of high concentration to an area of low concentration. Does not require energy. |
| Osmosis | the diffusion of water across a selectively perimeable membrane. |
| Solute | the substance that is dissolved in a solvent |
| Solvent | substance in which a solute is dissolved |
| Solution | solutes dissolved in solvent |
| Concentration | mass of solute in a given volume of solution |
| Concentration gradient | a difference in concentration in one place compared to another |
| Equilibrium | the solute concentration is uniform or equal everywhere in the solution. |
| Permiable | all molecules can cross the membrane |
| Semipermiable | only certain molecules can cross the membrane, others cannot cross |
| Selectively permeable | only certain molecules can cross the membrane, others cannot Impermeable - nothing can cross the membrane |
| Passive transport | movement across the membrane that does not require energy. Includes diffusion, osmosis, facilitated diffusion, and protein channels |
| Active transport | movement across the membrane that requires energy. Includes pumps and vesicles |
| Isotonic | the solute concentration inside the cell is the same as the solute concentration outside the cell |
| Hypertonic | Solute concentration outside cell is greater than inside cell. Cell will shrink. |
| Hypotonic | solute concentration outside cell is less than inside the cell. Cell will swell. |
| Vesicles | are small membrane sacs that pinch off of cell membranes |
| Endocytosis | vesicles used to bring materials into the cell. Uses ATP |