Transcript Diffusion/Osmosis

Passive Transport
Standard/Obj
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Know cells are enclosed within
semipermeable membranes that
regulate their interaction with their
surroundings.
Why do vegetables wilt?
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Homeostasis
biological balance between a cell or
an organism and its environment
Cell Membrane
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Lipid bilayer
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1.
2.
Passive Transport-movement of any
substance across a membrane w/o
use of chemical energy
Facilitated Diffusion: transport
proteins help move materials across
cell membrane
Gated Channel: protein controlled
opening (channel), some are
permanently open
Diffusion
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Process by which molecules spread from an
area of greater concentration to an area of
lesser concentration
Chemical energy not needed
Concentration gradient
Equilibrium reached
Osmosis
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Process by which water molecules
diffuse through a membrane from an
area of high concen. to area of low
concen.
1.
Hypertonic
Solution
-HIGHER solute
concentration. Cell
shrinks
2.
Hypotonic Solution
-LOWER solute
concentration.
Water diffuses into
cell causing to
swell possibly
burst.
3.
Isotonic Solution
-concen. of water inside and
outside the cell are equal (solute
concen. are equal)
-equilibrium
Turgor Pressurewater pressure in cell
ex. water pressure forces
cytoplasm and cell
membrane against the
cell wall in plants
1.
Plasmolysis-shrinking
of a cell from low
turgor pressure
(hyper)
2.
Cytolysis-cell takes in
so much water that it
bursts (hypo)
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