1. III. Cellular Transport

2. A. Structure of Plasma Membrane
Described as a Fluid Mosaic
Many different pieces moving around
Parts
Phospholipids
Two part molecules
Polar phosphate head
Nonpolar Lipid Tails
Form a double layer
Non-polar parts stay together

3. Selectively permeable
Hydrophobic (water fearing) molecules pass through
Hydrophilic (water loving) molecules bounce off
Divides Extracellular fluid from Cytosol

4. Cholesterol Proteins are Stabilizes the membrane Anchors Name tags
Transporters

5. B. Types of cellular transport
Passive transport
Requires no energy
Two Types
Diffusion
Osmosis
Active transport
Requires energy
Many types
Exocytosis
Endocytosis
Pumps

6. C. Diffusion
Movement of molecules from an area of high concentration to an area of lower concentration.
Why do the molecules move
Others bump into them
Animation

8. D. Osmosis Occurs through a barrier Is the diffusion of water
Water moves towards area of high solute concentration
Solute = What is dissolved
Solvent = what its dissolved in

9. 4. Effects of osmosis Tonicity referrers to the solute (salt)
Iso- = Same salt
Hyper- = Higher salt
Hypo- = Lower salt
Maintaining tonicity is part of homeostasis
Hypotonic
Hypertonic
Isotonic
Lysis
Crenated
No change

11. ACTIVE TRANSPORT

12. E. Exocytosis Movement of objects out of the cell
Vesicle binds to the membrane

13. F. Endocytosis Movement of large objects
Cytoskeleton changes membrane shape into a pseudopod (false foot)
Vesicle forms around object
Object is imported

14. White blood cell eating a bacterium

15. G. Receptor Mediated Endocytosis
Picky eating
Desired object binds to receptors
Like a key fits in a lock
Vesicle forms when receptors are full

16. H. Protein Pumps ATP (energy) is used to power the pump
Works against diffusion
Very important for homeostasis