1. CellularCellular
TransportTransport

2. Functions of the cell membrane.Functions of the cell membrane.
1. Provides boundary for cell
2. Selectively permeable- only
allows certain things to pass
through- “Picky”
Ex. Window screen
3. Maintains homeostasis:
balance within the cells

3. Relate the structure of the cellRelate the structure of the cell
membrane to its function.membrane to its function.
Membrane isMembrane is a lipida lipid
bilayerbilayer
fluid-mosaic modelfluid-mosaic model
Phospholipids:Phospholipids: fattyfatty
areas that attractareas that attract
(hydrophillic) and repel(hydrophillic) and repel
(hydrophobic) water(hydrophobic) water
Embedded proteins:Embedded proteins:
“bouncers”“bouncers”
1.1. Decide who goes in &Decide who goes in &
outout
2.2. Markers for recognitionMarkers for recognition

4. DiffusionDiffusion
movement of particles from high to
low concentration
Ex. Perfume & Body odor
OSMOSIS
movement of water from high
to low concentration.
Both
Go through bilayer
Do NOT require cell energy (passive
transport)
Move until equilibrium is reached
High
concentration
Low concentration
Osmosis Diffusion

5. Cells in solutions.Cells in solutions.

6. Compare the three types ofCompare the three types of
solutions.solutions.
ISOTONICISOTONIC: same strength: same strength
particles outside = particlesparticles outside = particles
insideinside
ISO- means “equal to”ISO- means “equal to”
Movement into cell=Movement into cell=
movement out of cellmovement out of cell

7. •HYPOTONIC:
concentration of dissolved
substances is lower outside
cell than inside cell
•HYPO means “below
strength”
•Water will move INTO cell
causing it to swell (it always
moves to where there is more
substances)
•Cells could rupture if the cell
takes in too much water
•This increases pressure
inside of cell (TURGOR
PRESSURE)

8. •HYPERTONIC:
concentration of dissolved
substances is higher
outside the cell
•HYPER means “above
strength”
•Water rushes OUT of cell
causing it to shrivel (water
rushes to where there is
more substances)
•Can result in
PLASMOLYSIS in plants
which causes wilting

9. •FACILITATED DIFFUSION:
•type of diffusion since
movement is from high to low
concentration, but this type
goes through a protein
channel rather than bilayer.
•Also Passive Transport
•Proteins –picky “bouncers”
Glucose
molecules
Protein
channelLow
Concentration
High
Concentration

10. ACTIVE TRANSPORT:ACTIVE TRANSPORT:
transporttransport againstagainst
concentration gradient;concentration gradient;
goes fromgoes from low to highlow to high
concentrationconcentration
Go through proteinGo through protein
channelchannel
This requires energy toThis requires energy to
move them into cell; ex:move them into cell; ex:
Na-K pumpNa-K pump
Molecule to
be carried
Molecule
being carried
Energy
Low
Concentration
High
Concentration

11. •Types of active transport:
•ENDOCYTOSIS: cells take
in large clumps of
substances
•Phagocytosis: “cell eating”
take in food
•Pinocytosis: “cell drinking”
take in water
•EXOCYTOSIS: cells move
substances out(exit)
ex: wastes

12. SummarySummary
Diffusion & OsmosisDiffusion & Osmosis/ high to low conc./ go in between/ high to low conc./ go in between
phospholipid spaces/ no energy=phospholipid spaces/ no energy= Passive transportPassive transport
Facilitated DiffusionFacilitated Diffusion- high to low/ no energy/ goes through- high to low/ no energy/ goes through
proteinprotein
Active transportActive transport- low to high conc./ requires energy/ goes- low to high conc./ requires energy/ goes
through proteinthrough protein
Ex. PartyEx. Party
`` 1. Air coming into a window screen1. Air coming into a window screen
2. Someone opens the door & you walk2. Someone opens the door & you walk
through (door represents protein)through (door represents protein)
3. someone goes through the back door that is3. someone goes through the back door that is
already openalready open
*coming in=Endocytosis going out= Exocytosis*coming in=Endocytosis going out= Exocytosis