a transmembrane protein that helps a certain substance or class of closely realted substances to cross the membrane
passage of water molecules through the membrane in certain cells is greatly facilitated by channel proteins known as?
the movement of molecules of any substance so that they spread out evenly into the available space
the region along which the density of a chemical substance increases or decreases
the diffusion of a substance across a biological membrane with no expenditure of energy
solute concentration is the same as that inside the cell; no net movement across the plasma membrane
when a plant cell shrivels, its plasma membrane pulls away from the wall-wilts/plant death
when polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane
the movement of a substance across a cell membrane agasint its concentration or electrochemical gradient, mediated by specific transport proteins and requiring an expenditure of energy
a transport protein in the plasma membrane of animal cells that actively transports sodium out of the cell and potassium into the cell-RELEASES ATP
a single ATP powered pump that transports a specific solute can indirectly drive the active transport of several other solutes in a mechanism called?
when cells secrete certain biological molecules by the fusion of vesicles with the plasma membrane
a type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes