How do necessary materials needed for cells get in? How do things get out?
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Every living cell exists in a liquid environment
Cell membrane regulates movement of
molecules from one side to another (selective
permeability)
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Diffusion
 Movement of particles from areas of
concentration to lower concentration!
 Examples? (Think about air freshener)
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Diffusion video!
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Draw a diagram of diffusion happening!
Include arrows to show where the particles
move.
Cell membranes have lipid bilayers
Particles that usually pass through are small and
uncharged
 What if something’s bigger…like glucose or ions
like Cl Proteins in the cell membrane act as carrier or
channels making it easy for certain molecules to
cross!
 Facilitated diffusion-the process in which
molecules that cannot directly diffuse across the
membrane pass through special protein
channels
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Facilitated Diffusion!
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Facilitated diffusion is helpful but it still
doesn’t require any extra energy from the
cell!

Draw a cell membrane and label where the
hydrophobic tail is and where the hydrophilic
head is 
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Diffusion of water through a selectively
permeable membrane

Think about the lipid bilayer…why do you
think water needs help getting through
membrane?

Water travels through an aquaporin water
channel proteins that allow water to pass
right through the membrane
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Osmotic Pressure the movement of water
out of or into the cell creates this force
Can cause cell to shrink, swell or stay the
same

Isotonic, Hypotonic and Hypertonic
Solutions!
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The movement of materials against a
concentration difference
Goes from ______ concentration to _______
concentration.
***Requires energy***
Usually carried out by protein pumps within
the membrane

Bulk materials, large molecules or clumps are
moved by two ways: exocytosis or
endocytosis

Exocytosis membrane surrounding the
material fuses with cell membrane, forcing
contents out of the cell

Process of taking material into a cell by means
of infolding or pockets.

The pocket breaks loose and forms a vesicle
within the cytoplasm.
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A type of endocytosis is phagocytosis where
an extension of the cytoplasm surrounds a
particle and packages it within a food vacuole.
The cell then engulfs it. Uses a considerable
amount of energy!!!!
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Endocytosis, Exocytosis and Phagocytosis!