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.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

2

3

14

(water)

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 = solventGlucose, Starch = solutes

http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/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]

Isotonic

HypotonicHypertonic

Part 3 pg. 85

Osmosis in Living Cells

Cellulose in cell wall

Osmosis in Red Blood Cells

Isotonic

Hypotonic

Hypertonic

• 0.9% saline

10% NaCl

Distilled water

Predictions?

Plasmolysis

Osmosis in Plant Cells

•.

10% NaCl

Distilled water

Hypertonic

Hypotonic

Predictions?

Plasmolysis

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

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