Biological Membrane Flashcards
fluid mosaic model of membrane structure
a model that describes the phospholipid bilayer as fluid and proposes that integral membrane proteins float freely in the lipid bilayer
endocytosis
process by which vesicles are internalized from the plasma membrane; often used to absorb or ingest molecular contents into the cell
integral membrane protein
protein that is permanently embedded in the cell membrane
transmembrane protein
integral membrane protein that spans the entire width of a cell membrane
osmosis
diffusion of water across a selectively permeable membrane due to solute differences on either side of the membrane
isotonic solutions
solutions separated by a membrane and containing an equal concentration of non-permeating solutes
hypotonic solution
solution with a lower concentration of non-permeating solutes than that of the solution on the other side of a membrane
hypertonic solution
solution with a higher concentration of non-permeating solutes than that of the solution on the other side of a membrane
facilitated diffusion (passive transport)
movement of molecules across a membrane via transport proteins without energy from ATP hydrolysis
active transport
movement of molecules across a membrane, typically against a concentration gradient, by transport proteins that require energy from ATP hydrolysis; this energy requirement can be direct (primary active transport) or indirect (secondary active transport)
electrochemical gradient
combined electrical and chemical (diffusion) forces acting on an ion between two sides of a cell membrane
membrane potential
electrical potential or voltage between the two sides of the plasma membrane
aquaporin
transport protein for the facilitated diffusion of water through a cell membrane
ion channel
transport protein for the facilitated diffusion of ion(s) through a cell membrane
ion pump
protein that moves ion(s) through a cell membrane by primary active transport