Diffusion and Osmosis
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?
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.mcgrawhill.com/sites/0072495855/studen
t_view0/chapter2/animation__ho
w_diffusion_works.html
(water)
1
2
3
4
Osmosis
•
Diffusion of water through a semipermeable 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/cha
pter2/animation__how_osmosis_works.html
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]
Hypertonic
Hypotonic
Isotonic
Part 3 pg. 85
Osmosis in Living Cells
Cellulose in
cell wall
Osmosis in Red Blood Cells
•
0.9% saline
Isotonic
10% NaCl
Plasmolysis
Distilled water
Predictions?
Hypertonic
Hypotonic
Osmosis in Plant Cells
Plasmolysis
•.
10% NaCl
Distilled water
Hypertonic
Predictions?
Hypotonic
Animations
Dialysis Bag Experiment
• http://ccollege.hccs.cc.tx.us/instru/Biology/AllStudy
Pages/Diffusion_Osmosis/Baggif.swf
Elodea Cell
• http://ccollege.hccs.cc.tx.us/instru/Biology/AllStudy
Pages/Diffusion_Osmosis/Elodeagif.swf
Osmosis
• http://ull.chemistry.uakron.edu/genobc/animations/o
smosis.mov
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
Effect of Water on RBC