Tonicity Day 1

Main Ideas: Need to move things in/out of cell; 3 ways to do this Things always move from high to low concentration Because membrane is selectively permeable, can choose whether to do this or not hyPERtonic – higher inside than should be hyPOtonic – lower inside than should be

What NEEDS to move Nutrients Meet energy demands Growth & repair Water Chemical reactions! Waste Maintain normal functioning

3 General Ways to Move Diffusion ** Transport Proteins Endocytosis/Exocytosis

Diffusion HIGH concentration to LOW concentration MOLECULES are moving Passive (no energy required)

Diffusion Constant back/forth until equal concentration

Factors affecting Diffusion Rate Concentration Gradient Size & shape of molecules Temperature Concentration gradient: a greater difference in concentration increases the rate of diffusion Size & shape of molecules: smaller molecules diffuse more quickly Temperature: heating speeds up diffusion

Osmosis Same ideas as diffusion, but WATER is moving Water easily moves across membrane

Osmosis Words Solute: particles dissolved in water Solvent: the water! Solution: combination of solute and solvent Osmotic Pressure: pressure to due osmosis movement Mr. Solute

Examples (don’t write!)

OSMOSIS Where is the solute concentration higher? Higher concentration of solute Lower concentration of solute

OSMOSIS Where is the water concentration higher? Higher concentration of solute Lower concentration of solute Lower concentration of WATER Higher concentration of WATER

Higher concentration of solute Lower concentration of solute OSMOSIS Where will the water go? Water movement Water movement Higher concentration of solute Lower concentration of solute Lower concentration of WATER Higher concentration of WATER

Tonicity (write!) ALWAYS comparing two areas Isotonic: same [ ] No net movement of water Hypertonic: more [ solute ] Hypotonic: less[ solute ]

Tonicity in a solution Solution Cell Isotonic No change Hypertonic Water rushes out; Cell SHRINKS Hypotonic Water rushes in; cell GROWS

Examples (don’t write!)

Which side is yellow hypertonic to? QUICK CHECK Which side is yellow hypertonic to? RIGHT Which side is yellow hypotonic to ? LEFT

WHERE WILL THE WATER GO? 80% H2O 90% H2O 20% Sugar 10% Sugar Water movement 90% H2O 10% Sugar Water movement

Once H2O finished moving, both sides are isotonic to each other WHERE WILL THE WATER GO? 85% H2O 15% Sugar Once H2O finished moving, both sides are isotonic to each other

EXAMPLE Where will the water go? 90% H2O 10% Sugar 80% H2O 20% Sugar Water movement Water movement

EXAMPLE What will the cell look like ? AFTER BEFORE Cell & beaker are isotonic

EXAMPLE Where will the water go? 70% H2O 30% Sugar 80% H2O 20% Sugar Water movement Water movement

EXAMPLE What will the cell look like ? AFTER BEFORE Cell & beaker are isotonic

MAXIMUM TO CELL SIZE? Can a cell get too small or too big? Absolutely!

To Do’s Provincial Q’s Sheet  right side page Dictionary: Isotonic, hypertonic, hypotonic, solute, solvent, diffusion