Differentiate between Osmosis and diffusion.ppt

Difference between osmosis and diffusion

1. OSMOSIS/DIFFUSION
GUIDED NOTES

2. Molecules are always moving
Molecules move randomly and bump into each
other and other barriers

3. Concentration gradient
Concentration Gradient -change in the concentration of a
substance from one area to another.

4. Diffusion
•Movementofmoleculesfromanareaofhigh
concentrationtoanareaoflowerconcentration.
•Factorsthataffecttherateofdiffusion:sizeof
molecules,sizeofporesinmembrane,
temperature,pressure,andconcentration.

5. Molecules in a solution tend to slowly spread apart
over time. This is diffusion.T
1
T
2 T
3
Diffusion

6. Diffusion
[High] [Low]
concentrated, high energy molecules
diffuse, low energy molecules

7. Diffusionwillcontinueuntilequilibriumisreached.
Thismeanstherewillbeanequaldistributionof
moleculesthroughoutthespace.Thisiswhyfood
coloringmovesthroughoutabeakerofwater;whyodors
smellstrongatfirstandthendisappearovertime.
Equilibrium,aresultofdiffusion,showstheuniformdistributionof
moleculesofdifferentsubstancesovertimeasindicatedinthe
abovediagram.

8. Which molecules will diffuse in each of
the figures below?
1
2
3
4
5 6

9. ANSWERS
1
2
3
4
5 6
No Movement

10. Osmosis–A Special kind of Diffusion
Diffusion of wateracross a
semi-permeable membrane (a
barrier that allows some
substances to pass but not
others). The cell membrane is
an example of this barrier. This
barrier allows small molecules
to pass through but large
molecules can’t pass through.
Example: Water

11. Osmosis
Osmosis is the movement of WATERacross a
semi-permeable membrane
At first the concentration of solute is very high
on the left.
But over time, the water moves across the
semi-permeable membrane and dilutes the
particles.

13. Hypotonic –The solution on one side of a membrane where the solute
concentration is less than on the other side. Hypotonic Solutions contain a low
concentration of soluterelative to another solution.
Hypertonic –The solution on one side of a membrane where the solute
concentration is greater than on the other side. Hypertonic Solutions contain a
high concentration of soluterelative to another solution.

14. Over time molecules will move across the
membrane until the concentration of
solutes is equal on both sides. This type of
solution is called ISOTONIC.

15. •Cytoplasm is a solution of water and solids
(solutes dissolved in the water).
•Water moves into and out of cells because of the
different concentrations of the solutes.
•Different kinds of cells react differently depending on
the solution they are in.
•Below are examples of red blood cells in different
types of solutions and shows what happened to the
red blood cells.

16. Turgor Pressure builds in the
cell and causes osmosis to stop
because of the rigid cell wall.
Plants will wilt when cells
lose water through osmosis.
Hypotonic
Solution
Hypertonic
Solution
PLANT CELLS

17. ELODEA CELLS
As viewed under the microscope

18. PASSIVE TRANSPORT
Passivetransportoccurswithoutexpenditureofenergy.
Moleculesmoveusingtheirownkineticenergy.Diffusionand
osmosisareexamplesofpassivetransport.Passivetransport
allowscellstogetwater,oxygenandothersmallmoleculesthat
theyneed.Italsoallowsthecelltogetridofwastesuchas
carbondioxide.
DIFFUSION
OSMOSIS

19. OSMOSIS and DIFFUSION

20. THE END