1. Active Transport cell uses energy (ATP)
actively moves molecules to where they are needed
Movement from an area of low concentration to an area of high concentration

2. Active Transport Protein Pumps
Protein Pumps -transport proteins that require energy to do work
Example: Sodium / Potassium Pumps are important in nerve responses.
Protein changes shape to move molecules: this requires energy!

3. Active Transport Endocytosis
Endocytosis: taking bulky material into a cell
“cell eating”
Uses energy
Cell membrane in-folds around food particle
forms food vacuole & digests food
This is how white blood cells eat bacteria!

4. Types of Active Transport Exocytosis
Exocytosis: Forces material out of cell in bulk
membrane surrounding the material fuses with cell membrane
Cell changes shape – requires energy
EX: Hormones or wastes released from cell

6. Effects of Water on Life
Osmosis- diffusion of water through a selectively permeable membrane
Water is so small and there is so much of it the cell can’t control its movement through the cell membrane.

7. Effects of Water on Cells
Dissolved molecules (i.e. glucose, starch) are called solutes. These can evenly mix throughout water, the solvent.
Water = solvent
Glucose, Starch = solutes

8. Effect of Water on Cells
Hypertonic Environment
High [solute], low [water] outside the cell.
Water will diffuse out of the cell causing the cell to shrink.
Isotonic Environment
[water] = [solute]
Water moves in and out of the cell at a constant rate helping maintain equilibrium.
Hypotonic Environment
High [water], low [solute] outside the cell.
Water will diffuse into the cell, causing the cell to swell.

9. Osmosis in Living Cells
Cellulose in cell wall