1. Schedule Why was it so darn cold? Go over quizzes Current event Membranes Membranes worksheet (finish for HW as needed) Tomorrow: Review membranes, Osmosis/Diffusion Membranes Quiz next Monday Mini-unit test next Wednesday

2. DNA Draw how a water molecule surrounds a cation like Na+

3. Water Soluble

4. Membrane Structure and Function

5. Hydrophobic Vs. Hydrophilic Water-fearing Fats, oils, rubbers Non-polar Water-loving Polar, ionic Has some charge

6. Amphipathic Molecules Have both hydrophilic and hydrophobic regions Phospholipids have hydrophilic heads and hydrophobic tails

7. Soaps/Detergents

8. Phospholipids

9. Phospholipid Bilayer Phospholipids naturally arrange themselves to keep hydrophobic portions away from water

10. Membranes Both wrap the entire cell and individual organelles Very movable – like play-dough

11. Fluid Mosaic Model Proteins are embedded in the membrane These proteins have many different functions

12. Membrane Protein Functions Transport Enzymatic Activity Binding of messengers Intercellular connections Cell recognition Attachment

13. Membrane Carbohydrates Important in cell-cell recognition Short polysaccharides Often bonded to proteins (glycoproteins) Distinguish cells – i.e. blood types

15. What Makes Each Membrane Different? The proteins and carbohydrates present E.g. thylakoid membranes have chlorophyll proteins, red blood cells have A/B markers etc.

16. Special Membranes = Special Organelles Controls what gets into the organelle. So mitochondria has only the materials necessary for respiration – nothing else to get in the way!

17. Selective Permeability Membrane is selective in what molecules can pass through and how quickly they pass Energy must sometimes be used to transport molecules

18. Simple Permeability Small non-polar molecules rapidly pass through membrane Very small polar molecules can slip through Larger polar molecules cannot Very impermeable to ions

19. Cell Wall v. Plasma Membrane Rigid Carbohydrates Controls structure Not in animal cells Flexible Phospholipids Controls entry In all cells