Transport across cell membrane Flashcards
simple diffusion
the passive movement of molecules from areas of high concentration to areas of low concentration (down the concentration gradient)
moves non polar, hydrophobic small molecules (oxygen, carbon dioxide)
facilitated diffusion
movement of a substance across a membrane with the help of a protein channel
moves polar, hydrophilic, large molecules (ions, glucose)
protein channel
pores or holes in the membrane that let specific substances through
osmosis
movement of water molecules from a region of high concentration to a region where concentration is low, through a selectively permeable membrane
active transport
movement of molecules across a semipermeable membrane that requires energy
carrier proteins
carrier protein a membrane protein that undergoes conformational change to transport molecules across a membrane
tonicity
a measure of the relative concentration of solutes on either side of a semipermeable membrane
hypertonic
solution with a higher solute concentration when compared to another solution
isotonic
a solution with the same solute concentration as another solution
hypotonic
solution with a lower solute concentration when compared to another solution
exocytosis
a type of bulk transport that moves large substances out of the cell
endocytosis
a type of bulk transport that moves large substances into the cell
bulk transport
the movement of groups of molecules across the plasma membrane
phagocytosis
endocytosis of solid
material or food particles
pinocytosis
endocytosis of liquid or dissolved substances
