Osmosis

EQ What is osmosis and why is it important to cells?

Record

• New observations– Describe each potatoe

• How were the potatoes in each concentration different?

Osmosis

• Osmosis is when water moves through a semi permeable membrane.

• Osmosis is DIFFUSION of Waterthrough a membrane.

How does salt affect the flow of water?

• If a potato was strong and hard to flex would it be full of water or empty?

• If a potato was flimsy and shriveled would it be full of water or more empty?

• Which potato was flimsy?– So did it gain or lose water?

• Which potato was firm– So did it gain or lose water

Potato

• 1 ml 4ml 10ml

Solutions

• If you are in salty water does that make your cell gain or lose water?

High to Low

• Diffusion and osmosis always move from high to low concentration.

• High Water concentration =Low particle concentration

Low particle concentration=High water concentration

• Add water to juice you water it down• Add salt to water. Water is less concentrated.

Water moves towards the particles

• Add water to juice you water it down• Add salt to water. Water is less concentrated.

• If you add something to water, you lower the concentration of water.

• Concentration is how crowded the molecules are. – Think about “watering down your soda”

Water onlyWater with salt. Water less concentrated

Draw a cell

• How could I make water come out of a cell?

• How could I make water go into a cell?

• Draw the number of salt particles inside and outside to create osmosis.

• Draw a cell that would absorb water. • Draw a cell that would release water.

How does this affect cells?

Equilibrium Shriveled Swollen

How does this affect cells?

Equilibrium Shriveled Swollen

Which solution is:Isotonic?Hypertonic?Hypotonic?

Application questions:

What happens to your cells if you eat too much salt?

What happens if you put a shark in fresh water?

Why do slugs die if you pour salt on them?

Why does a plant wilt?Why does a plant get firm after you water it?

• What part of the cell

Isotonic

Hypotonic

Hypertonic

Effect of Water on RBC

Summary

• What is osmosis.

• What does adding salt do to the concentration of water?

• Why will a cell shrivel up?• Why will a cell swell up?

Osmosis

EQ What is osmosis and how does it affect cells?

Warmup. How is osmosis like diffusion? What is the difference between diffusion and osmosis?What does salt do to the concentration of water?If we want to make water come OUT of a cell, where would we put salt particles?

Review for Quiz

What is the difference between osmosis and diffusion?

VocabSemipermeable MembraneOsmosisDiffusion.

What causes a cell to shrivel?What causes a cell to swell up?

Salty Potato

• Pour a small amount of salt into one potatoes well.

• Predict what you think will happen.

• After 15mins we will observe changes.

With your group:Which beaker has more salt INSIDE the cellWhich beaker has more salt OUTSIDE the cellWhich beaker has a balance of salt inside and outside

IsotonicEverything balancedHypotonic

Cell swellsThink Hippotonic, fat cellSalt inside cell

HypertonicCell shrivelsSalt outside cellThink HYPER. Water cant sit still so runs out of cell.

Water moves from High to Low Concentration, Salt lowers concentration.

Think water is attracted to salt.

Semi Permeable Membranes

• Semi permeable• How can bigMolecules get in theCell?

Think of the oil

Endocytosis

What do you think it means?

Come up with a definition with your group

Endocytosis is when the cell membrane wraps around and engulfs nutrients

Exocytosis

• What do you think Exocytosis means?

• Opposite of endocytosis.

• Think: Endo for Enter… Exo for Exit

• Page 56 in the book. • Read and answer review questions.

Flash cards-Quiz will have the followingDiffusionOsmosisSemiPermeable membraneEndocytosisExocytosisWhich way does diffusion happen. Which way will water flow in osmosis. Be able to draw the three cells. Draw a cell with size of cell and

where the salt particles are. IsotonicHypertonicHypotonic

Endocytosis- Exocytosis

• http://www.stolaf.edu/people/giannini/flashanimat/cellstructures/phagocitosis.swf