Membrane Function Flashcards
what are the basic membrane functions?
- maintain internal cell environment at a steady state regardless of changes in the external environment
- acts a selective barrier regulating the movement of substances into and out of the cell
what are the 3 main types of transport?
passive
active
bulk membrane
what are the types of passive transport
simple duffusion
facilitated diffusion (channel, carrier)
osmosis
what is the type of active transport
pump
types of bulk membrane transport
- endosytosis
- exocytosis
diffusion
substance spreads out since molecules are constantly in motion and bumping into each other
passive transport definition
does not require energy and molecules move from high to low concentration
simple diffusion/transfer
movement accross a semi-permeable membrane, down a concetration gradient, no energy required, continues until equilibrium is achieved
what type of molecules go through simple diffusion?
O2 and CO2
facilitated transport
across a semi permeable membrane passive transport, continues until equilibrium is achieve, moves through a channel or carrier proteins
what types of particles go through channel proteins
small dissolved charged molecules like ions
aquaporins
a specific type of channel protein that facilitate the movement of water molecules across a membrane
carrier proteins
acts like turnstile/revolving door, underoges conformational change to allow molecules through
types of particles through carrier proteins
moves a variety of substnaces from charged particles to large uncharged molecules
uniport
movement of a single molecule in one direction - all channel proteins
symport
movement of 2 molecules in the same direction
antiport
movement of 2 molecules in opposite directions
osmosis
diffusion of water
describe osmosis
water moves from an area of high water concentration to an area of low water concentration
tonicity
the concentration of solutes in the environment surrounding the cell
isotonic
the same - equal movement in and out of cell
hypotonic
less concentration of solutes outside the cell
hypertonic
concentration of solutes is more outside the cell
osmotic lysis
animal cell bursts