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17 Cards in this Set

  • Front
  • Back
passive transport
movement across the cellmembrane that doesnt require energy from the cell
concentration gradient
a difference in teh concentration of a substance across a space
a condition in which the concentration fo substances is equal throughout space
the movement of substanecs form an are of high concentration to an area of lower concentration caused by random motion of particles of the substance
the diffion of water thorugh a selectively permaeable membrane
hypertonic solution
lowers free water molecule concentration
cell shrinks
water out
hypotonic solution
higher free water molecule concentration
cell swells
water in
isotonic solution
same free water molecule concentration
cell stays same
in out at equal rate
ion channel
transport protein with a polar pore through which ions can pass
carrier protein
a kind of transport protein that can bind toa specific substance on one side of the cell memebrane, carry the substance across the cell membrance and release it on the other side.
faciliated diffusion
when carrier proteins are used to transport specific substances such as amino acids and sugars down their concentration gradient.
active transport
the transport of a substance across the cell membrane against its concentration gradient
transports three sodium ions Na+, out the cell and two potassium ions, K+, into the cell
the movement of a substance into a cell by a vesicle
the movement of a substance by a cesicle to the outside of a cell
receptor protein
a protein that binds to a specific signal molecule, enabling the cell to respond tothe signal molecule
second messenger
acts asa a signal moleculee in the cytoplasm. amplifies the signal of the first messenger