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chapter 5 section 1
passive transport
Term | Definition |
---|---|
passive transport | the cross of the cell membrane without any input of energy by the cell |
diffusion | the movement of molecules from an area of higher concentration to an are of lower concentration |
concentration gradient | the difference in the concentration of the molecules across a distance |
equilibrium | the concentration of molecules will be the same throughout the space the molecules occupy |
osmosis | the process by which water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration |
hypertonic | when the concentration of solute molecules outside the cell is lower than the concentration in the cytosol |
hypotonic | when the concentration of solute molecules outside the cell is higher than the concentration in the cytosol |
isotonic | when the concentration of solutes outside and inside the cell are equal |
contractile vacuole | organelles that remove water. they collect the excess water and ten contract, pumping the water out of the cell |
turgor pressure | the pressure that water molecules exert against the cell wall |
plasmolysis | in a hypertonic environment, water leaves he cell through osmosis. the cell shrinks away from the cell walls and the turgor pressure is lost. this is also the main reason plants wilt of they don't get enough water. |
cytolysis | the bursting if cells |
facilitated diffusion | the process that is used for molecules that cannot readily diffuse through cell membranes, even when there is a concentration gradient across the cell membrane |
carrier protein | specific proteins in the membrane |
ion channel | membrane proteins that transport ions from higher to lower concentrations |