1. Membranes Phospholipids and Bilayers

3. What do cell membranes consist of? Experiment: ABCDEF 10 cc of milk 10 cc of vinegar 10 cc of oil 10 cc of vinegar piece of red cabbage 10 cc of vinegar 10 cc of milk 10 cc of water 5 drops of washing up liquid 10 cc of oil 10 cc of water 5 drops of washing up liquid piece of red cabbage 10 cc of water 5 drops of washing up liquid results: milk clotted results: oil floats on top results: bright pink colour leaks out results: milk emulsified (little droplets) results: oil emulsified (little droplets) results: violet colour leaks out Conclusions: Cell membranes consist of proteins and fats (lipids)

8. Lipid packing

9. Arrangements of lipids in aqueous media Hydrophobic surfaces such as fatty acid chains aggregate in aqueous solutions, caused by aversion of water molecules to hydrophobic surfaces which force the water into ordered structures. Alternative structures with the hydrophobic surfaces as compact as possible are favoured.

13. Membrane fluidity: Frye-Edidin experiment

15. Frye-Edidin experiment