1. CELL TRANSPORT

2. Homeostasis and Transport
Homeostasis – the stable internal conditions of a living thing; maintaining a stable internal environment

3. Maintaining a Balance
Cells must keep the proper concentration of nutrients and water and eliminate wastes.
Cells die without homeostasis.
The plasma membrane is selectively permeable – it will allow some things to pass through, while blocking other things.

4. Passive Transport
Molecules move along a concentration gradient – the difference in concentration of the molecules in a space.
3 Types of transport:
Diffusion, osmosis and facilitated diffusion

5. Diffusion
Diffusion – the random movement of molecules from an area of high concentration to an area of low concentration until dynamic equilibrium is reached
Perfume, food coloring, O2, CO2

6. Osmosis
The diffusion of water across a selectively permeable membrane, from an area of higher concentration to an area of lower concentration until dynamic equilibrium is reached.

7. 3 types of solutions/cell environments
The direction of osmosis is determined by the type of solution a cell is in:
Hypertonic – the concentration of solute molecules is higher outside the cell than inside,
Hypotonic – the concentration is higher inside than outside, or
Isotonic – the concentration is the same

8. Cells in ISOTONIC solution

9. Cells in HYPOTONIC solution

10. Cells in HYPERTONIC solution

12. Facilitated Diffusion
A process in which substances move down their concentration gradient across the plasma membrane with the help of transport (carrier) protein molecules.
Examples: Sugars and amino acids

13. Active Transport
Movement of molecules and ions against the concentration gradient
Moves in the direction of Low  High
Energy is used
Example: Transport proteins bind to ions, used energy to change shape, flipping ion into cell.

14. CELL TRANSPORT
PASSIVE
ACTIVE
DIFFUSION
OSMOSIS
FACILITATED DIFFUSION

15. Diffusion
Osmosis
Facilitated diffusion
Active transport
Takes energy?
With or against the concentration gradient?
Requires a protein?
What kind of molecules

16. Cell Membrane
Organized as double layer of phospholipids called a lipid bilayer.

17. Cell Membrane
Phospholipids have a hydrophilic head and a hydrophobic tail
Hydrophillic – water “loving”
Hydrophobic – water “fearing”
These interactions results in a selectively permeable membrane
This helps determine what substances enter and leave the cell

18. Cell Membrane
Proteins are also embedded in the lipid bilayer of the cell membrane
This helps recognize substances, which can pass through the cell