1. Cellular Transport

2. Diffusion
the net movement of molecules from an area of high concentration to an area of low concentration
Example: the spread of brownies through the house as they bake.
Concentration Gradient - a gradual change in the concentration of solutes in a solution as a function of distance through a solution.

3. Cellular Transport
Osmosis– the diffusion of water
Water moves across a plasma membrane from an area of HIGHER concentration to an area of LOWER concentration

4. Question
What is Osmosis?

5. Solution– mixture of two parts: solute & solvent
solute– the molecules that are dissolved
solvent – the molecules they are dissolved IN

6. solutions Isotonic solution
a. solution has the same concentration of solute molecules as the cell
b. solution remains UNCHANGED
can even burst!)

7. Hypertonic solution
a. solution has greater concentration of solute molecules than the cell
b. cell looses water and shrinks
Hypotonic solution
a. solution has a smaller concentration of solute molecules that the cell
b. cell gains water and swells (can even burst!)

8. Question
What happens to a cell in a hypertonic, hypotonic and isotonic solution?

9. Cell Transport
Passive Transport – cell uses no energy to move substances across cell

10. Cellular Transport
Facilitated Transport – transport proteins help substances move across the membrane 

11. Active Transport– movement of molecules that REQUIRES ENERGY
Molecules can move across a plasma membrane or against the concentration gradient (from lower concentration to higher concentration)

13. Question
What is the difference between passive and facilitated transport?

15. Movement of Large Molecules
Endocytosis- material engulfed by a portion of the plasma membrane
Phagocytosis (food), pinocytosis(water)
Exocytosis - cell expels wastes