16 terms


passive transport
The movement of materials through a cell membrane without using energy
concertration gradient
the difference in concentration of a substance across space.
the movement of molecules from an area of higher concentration to an area of lower concentration
diffusion of water through a selectively permeable membrane
Hypertonic solution
a solution that causes a cell to shrink because of osmosis
hypotonic solution
a solution that causes a cell to swell because of osmosis
isotonic solution
a solution that produces no change in cell volume because of osmosis
Ion channel
a transport protein with a polar pore through which ions can pass
carrier protein
a protein that transports substances across a cell membrane
Facilitated diffusion
the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins
active transport
the movement of materials through a cell membrane using energy
sodium-potassium pump
a carrier protein that actively transports K+ ions into and Na+ ions out of cells
the movement of a substance into a cell by a vesicle
process by which vesicles release their contents outside the cell
receptor protein
a protein that binds specific signal molecules, which causes the cell to respond
Second messenger
acts as a signal molecule in the cytoplasm