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Definitions
CELL MEMBRANE
Diffusion through cell boundaries
Osmosis
Active transport
100
what is lipid bilayer
double - layered sheet that forms the core of nearly all cell membranes
100
what are the main functions of the cell membrane and the cell wall
the cell membrane regulates what enters and leaves the cell and also provides protection and support
100
what happens during diffusion
because diffusion depends upon random particle movements substances diffuse across membranes without requiring the cell to use energy
100
what is osmosis
osmosis is the diffusion of water through a selectively permeable membrane
100
as powerful as diffusion is cells sometimes must move _________ in the _____________ direction
materials , opposite
200
concentration of a solution is the ...
the mass of the solute in a given volume of a solution or mass/ volume
200
in addition to lipids most cell membranes contain
protein
200
the cytoplasm of a cell contains a solution of many different
substances in water
200
water passes quite easily across most membranes even though many
solute molecules cannot
200
the active transport of small molecules or ions across a cell membrane is generally carried out by
pumps
300
process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
diffusion
300
the composition of nearly all cell membranes is
double - layered
300
the first solution is __________ as concentrated as the second solution
twice
300
fortunately cell in large organism are not in danger of
bursting
300
larger molecules and clumps of material can also be actively trasported across the cell membrane by process known as
endocytosis and exocytosis
400
what is the dilute sugar solution
hypotonic
400
many of the carbohydrates act like
chemical identification
400
even when ________ is reached particles of a solution will continue to ___________
equilibrium ,move
400
because the cell is filled with salts sugars proteins and other molecules it
will almost always be hypertonic to fresh water
400
the transport of these larger materials sometimes involves changes the
shape of the cell membrane
500
when the concentration of the solute is the same throughout a system the system has reached
equilibrium
500
some of the proteins form channels and pumps that help to move material across the
cell membrane
500
what do diffusion and equilibrium have to do with cell membranes
suppose a substance is present in unequal concentrations on either side of a cell membrane
500
the cell walls prevent the cells from expanding even under
tremendous osmotic pressure
500
in a process similar to ___________ many cells take up ____________ from the surrounding environment
endocytosis, liquid