The document explains the processes of diffusion and osmosis, including their definitions and mechanisms, using examples from a gummi bear lab and dialysis bag experiments. It discusses the effects of different water concentrations on cells in hypertonic, hypotonic, and isotonic environments, detailing processes such as plasmolysis and turgor pressure. Additionally, it covers the concepts of passive and active transport of molecules across semi-permeable membranes.

1. Diffusion and Osmosis

2. TSWBAT identify the process of osmosis and
diffusion via the gummi bear lab
-analyze diffusion through a sand baggie and
apply the concepts of hypotonic, hypertonic, and
isotonic to the activity
• On a blank sheet of paper
– Write the equation for cellular respiration.
– Where does cellular respiration occur in the
cell?
– List the organelles that help to make proteins
– What is the difference between the rough and
the smooth endoplasmic reticulum?

3. Diffusion
• Solvent – what dissolve something
• Solute – what is being dissolved
• Solute molecules moving from an area of
high concentration to an area of low
concentration
– Random motion drives diffusion
– Movement is based on kinetic energy
(speed), charge, and mass of
molecules
– Equilibrium is reached when there is
an even distribution of solute
molecules
– http://highered.mcgraw-hill.com/
sites/0072495855/
student_view0/chapter2/
animation__how_diffusion_works
.html
2
3
1
4
(water)

4. Osmosis
• Diffusion of water through a semi-
permeable membrane
– Semi-permeable: permeable to
solvents (WATER), but not to
large molecules
– High [water] to low [water]
• Dissolved molecules (i.e. glucose,
starch) are called solutes
• REMEMBER:
Water = solvent
Glucose, Starch = solutes
http://highered.mcgrawhill.com/sites/0072495855/student_view0/
chapter2/animation__how_osmosis_works.html

5. Effect of Water on Cells
• Hypertonic Environment
– High [solute], low [water]
– The cell will shrink
– Plasmolysis – cell death
Hypotonic Environment
– High [water], low [solute]
– Plants – turgor pressure – plant
like this!!
– Animals – cytolysis – cell
bursting
• Isotonic Environment
– [water] = [solute]
Isotonic
Hypotonic
Hypertonic
Part 3 pg. 85

6. Osmosis in Living Cells
Cellulose in
cell wall

7. Osmosis in Red Blood Cells
Isotonic
Hypotonic
Hypertonic
•
0.9% saline
10% NaCl
Distilled water
Predictions?
Plasmolysis

8. Osmosis in Plant Cells
•.
10% NaCl
Distilled water
Hypertonic
Hypotonic
Predictions?
Plasmolysis

9. Animations
Dialysis Bag Experiment
• http://ccollege.hccs.cc.tx.us/instru/Biology/
AllStudyPages/Diffusion_Osmosis/Baggif.swf
Elodea Cell
• http://ccollege.hccs.cc.tx.us/instru/Biology/
AllStudyPages/Diffusion_Osmosis/Elodeagif.swf
Osmosis
• http://ull.chemistry.uakron.edu/genobc/animations/
osmosis.mov

10. Transportation of Molecules
• Passive Transport
-Movement of molecules across a
semi-permeable membrane
- no energy required
• Active Transport
-Movement of molecules across a
semi-permeable membrane against a
concentration gradient with a
protein
- ENERGY – ATP
• Facilitated Diffusion
-Movement of molecules across a
semi-permeable membrane with a
protein
- no energy required

11. Effect of Water on RBC