| A | B |
|---|
| concentration gradient | a difference in the concentration of a substance across a distance |
| facilitated diffusion | the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins |
| hypotoic | describes a solution whose solute concentration is lower than the solute concentration inside a cell |
| sodium potassium pump | a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into a cell |
| diffusion | the movement of particles from regions of higher density to regions of lower density |
| endocytosis | the process by which a cell membrane surrounds a particle and encloses the particle in a vesicle to bring the particle into the cell |
| ion channel | a pore i na cell membrane through which ions can pass |
| isotonic solution | a solution whose solute concentratin is equeal to the solute concentration inside a cell |
| second messenger | a molecule that is generated when a specific substance attaches to a receptor on the outside of a cell membrane, which produces a change in cellular function |
| active transport | the movement of chemical substances, usually across the cell membrane, against a concentration gradient' requires cells to use energy |
| carrier protein | a protein that transports substances across a cell membrane |
| receptor protein | a protein that binds specific signal molecules, which causes the cell to repsond |
| equilibrium | in chemistry, the state in which a chemical process and the reverse chemical process occur at the same rate such that the concentrations of reactants and products do not change |
| osmosis | the diffusioin of water or another solvent from a more dilute solution (of a solute) to a more concentrated solutioin (of the solute) through a membrane that is permeable to the solvent |
| passive transport | the movement of substances across a cell membrane without the use of energy by the cell |
| hypertonic | describes a solution whose solute contration is higher than the solute concentration inside a cell |
| endocytosis | the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out |
