Ch. 8 Membrane Structure and Function

1. Ch. 8 Membrane Structure and Function AP Biology Crosby High School

2. Two types of Proteins • Integral protein • Penetrate through the lipid bilayer • Peripheral protein • Loosely bound to surface of membrane

3. Membrane Carbohydrate • Cell-cell recognition • Sorts cells during development • Identify foreign cells • Oligosaccharides • Bound to either lipids or proteins • Act as markers to distinguish one cell from another

4. Membrane Reversal • Extracellular face is the same as inside face of ER, Golgi and Vesicles • Flips inside-out when incorporated into cell membrane

5. Permiability • Lipid bilayer • Hydrophobic compounds cross membrane • Polar or charged particles can not • Transport proteins • Creates hydrophilic channels • Some bind and move • Specificity

6. Passive Transport • Down concentration gradient • Uphill vs. downhill • Proceed to equilibrium • Increases Entropy by mixing • Does not use ATP • This does not require energy therefore ATP is not used

7. Osmosis • Diffusion of water • Relies on solute concentration • Hypotonic: lower solute concentration • Hypertonic: higher solute concentration • Isotonic: same solute concentration • Moves from Hypotonic  Hypertonic

8. Osmoregulation and Cell Survival • Paramecium use contractile vacuole • Cells with walls • Turgid • Flaccid • Plasmolysis

9. Facilitated Diffusion • Transport proteins create channels • Aquaporins • Gated channels • Bind and change shape

10. Active Transport • Requires work to transport uphill • Expends energy • Energy is provided by ATP • Sodium-potassium pump

11. Passive vs. Active Transport