1. CELLULAR TRANSPORT

2. CELL MEMBRANE
All cells have cell membranes
The functions of the cell membrane are
Controls what enters and exits the cell to maintain an internal balance called homeostasis
Provides protection and support for the cell

3. STRUCTURE OF CELL MEMBRANE
Lipid bilayer = 2 layers of phospholipids
Phospholipids have a hydrophilic head and a hydrophobic tail
Hydrophilic = water loving
Hydrophobic = water fearing

4. Cell Membrane

5. CELL MEMBRANE & TRANSPORT
Cell membranes are selectively permeable: it allows some molecules in and keeps other molecules out
The structure of the cell membrane helps it be selective
Molecules in motion have kinetic energy

6. TYPES OF CELLULAR TRANSPORT
PASSIVE TRANSPORT
Cell does not use energy
ACTIVE TRANSPORT
Cell has to use energy
DIFFUSION
PROTEIN PUMPS
FACILITATED DIFFUSION
ENDOCYTOSIS
OSMOSIS
EXOCYTOSIS

7. PASSIVE TRANSPORT Cell uses NO energy Molecules move randomly
Molecules go from an area of HIGH concentration to LOW concentration
3 types : diffusion, facilitated diffusion, osmosis

8. 1. DIFFUSION
Diffusion: random movement of particles from an area of high conc. to an area of low conc.
Diffusion continues until all molecules are evenly spaced (equilibrium is reached)
Molecules will still move around but stay spread out

9. Animation
1. DIFFUSION

10. 2. FACILITATED DIFFUSION
Diffusion of specific particles through transport proteins found in the membrane
Transport Proteins are specific – they “select” only certain molecules to cross the membrane
Also goes down a concentration gradient (HIGH → LOW)

11. 2. FACILITATED DIFFUSION
Animation
2. FACILITATED DIFFUSION

12. 3. OSMOSIS Diffusion of water through a selectively permeable membrane
Many molecules dissolve in water
Molecule is the solute
Water is a solvent
Osmosis is diffusion of water from high concentration to low concentration

13. Animation
3. OSMOSIS
SALT SUCKS!

14. TYPES OF SOLUTIONS HYPERTONIC SOLUTION ISOTONIC SOLUTION
HYPOTONIC SOLUTION

15. 1. HYPERTONIC
The solution has a higher concentration of solutes and a lower concentration of water than inside the cell.
OUTSIDE CELL: High solute/Low water
Water goes from inside the cell to outside
Cell SHRINKS

16. 2. ISOTONIC
The solution has an equal concentration inside and outside the cell.
Water moves equally in both directions
Cell stays the same size

17. 3. HYPOTONIC
The solution has a lower concentration of solutes and a higher concentration of water than inside the cell.
OUTSIDE CELL: Low solute/High water
Water goes from solution into the cell
Cell SWELLS & BURSTS

18. TYPES OF SOLUTIONS

19. ACTIVE TRANSPORT Cell has to use energy
Happens AGAINST a concentration gradient
Molecules go from LOW concentration to HIGH concentration
Difference between active and passive transport is the direction of movement

20. 1. PROTEIN PUMPS
Transport proteins that require energy (ATP) move the molecules in and out
Example: Sodium/Potassium Pumps

21. 1. PROTEIN PUMPS

22. 2. ENDOCYTOSIS Transporting bulky material into a cell Uses energy
Cell membrane in-folds
around food particle
“Cell Eating”
Forms food vacuole & digests food
This is how white blood cells eat bacteria!

23. 2. ENDOCYTOSIS
PHAGOCYTOSIS
PINOCYTOSIS

24. ACTIVE VS PASSIVE TRANSPORT