bio 202 - ch 7 membrane structure and function

pinocytosis

type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes

gated channel

transmembrane protein channel that opens or closes in response to a specific signal

hypotonic

referring to a solution that has a lower solute concentration, cell will swell

hypertonic

reffering to a solution with a higher solute concentration, cell will shrivel

ion channel

transmembrane protein channel that allows specific ions to diffuse across the membrane down its concentration or gradient

transport protein

transmembrane protein that helps a certain substance cross the membrane

membrane potential

difference in voltage across a cells plasma membrane due to the differential distribution of ions, affects the activity of excitable cells and the movement of all charged substances

diffusion

the random motion of particles

cotransport

movement of one solute drives the movement of the second

electrochemical gradient

diffusion gradient of an ion which is affected by both chemical and electrical force of ions

osmoregulation

solute concentrations and water balance in a cell

aquaporin

channel protein in a cellular membrane that specifically facilitates osmosis

passive transport

movement of particles with their gradient, no energy needed

facilitated diffusion

movement of particles down their gradient with the assistance of transmembrane transport proteins, no energy needed

electrogenic pump

active transport protein that generates voltage across a membrane while pumping ions

transmembrane proein

type of integral protein that spans the entire membrane

peripheral protein

protein loosely bound to the surface of a membrane or to part of an integral protein, not embedded in the lipid layer

tonicity

ability of a solution surrounding a cell to gain or lose water

integral protein

an amphipathic transmembrane protein

turgid

swollen or distended, plant cells

fluid mosaic model

model of cell membrane structure which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer

glycolipid

lipid with one or more covalently attached carbohydrates

sodium potassium pump

transport protein in the plasma membrane of animal cells that actively transport sodium out of the cell and potassium in

receptor mediated endocytosis

move molecules into a cell by infolding of vesicles containing proteins with receptor sites specific to the molecules being taken in, allow cell to get bulk quantities of a specific substance

active transport

movement of particles against the gradient, needs energy

plasmolysis

in walled cells the cytoplasm shrivels and pulls away from the cell wall

glycoprotein

protein with one or more covalently attached carbohydrates

phagocytosis

cellular eating

isotonic

solution solute concentration is equal to cell

proton pump

active transport protein that uses ATP to transport H+ out of a cell against the gradient, generates membrane potential

exocytosis

vesicles transported out of the cell