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Biology Quizlet #22
15 terms quater 4
Term | Definition |
---|---|
active transport | Energy-requiring process that moves material across a cell membrane against a concentration difference |
exocytosis | release of substances out a cell by the fusion of a vesicle with the membrane. |
endocytosis | A process in which a cell engulfs extracellular material through an inward folding of its plasma membrane. |
Receptor | on or in a cell, a specific protein to whose shape fits that of a specific molecular messenger, such as a hormone |
hydrophilic | Attracted to water |
hydrophobic | water hating |
Phospholopid Bilayer | two phospholipid layers with the phosphate heads on the outsides and the lipid tails on the insides |
selectively permeable | a property of cell membranes that allows some substances to pass through, while others cannot |
Diffusion | Movement of molecules from an area of higher concentration to an area of lower concentration. |
facilitated diffusion | Movement of specific molecules across cell membranes through protein channels from high to low concentration |
Osmosis | Diffusion of water through a selectively permeable membrane |
isotonic solution | A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution |
hypotonic solution | a solution that causes a cell to swell because of osmosis. Solute concentration is higher in the cell. |
hypertonic solution | a solution that causes a cell to shrink because of osmosis. Solute concentration is lower in the cell. |
passive transport | the movement of substances across a cell membrane without the use of energy by the cell |