Session 2.3a - Workbook Notes - Session ILO Flashcards
List the main kinds of lipids
- Phospholipids
- Glycolipids
- Sphingomyelin
- Cholesterol
List the general properties of fatty acids
- Hydrophobic flexible tails
Describe the properties of amphipathic molecules
- Have a hydrophobic and hydrophilic end
Explain the process of formation of lipid
bilayer
Phospholipid bilayer with 45% cholesterol and proteins studded in
Distinguish peripheral from integral membrane proteins
Peripheral - on top
Integral - transmembrane
Explain the forces associating peripheral and integral membrane proteins with the membrane
Peripheral - weak
Integral - stronger?
Describe in general terms the mechanism of membrane insertion of integral proteins
- SS/SRP/DP/SP mechanism
Describe in general terms the features of integral membrane proteins which explains their topology in the membrane
- Stop-transfer sequence which is hydrophobic
- Signal peptidase cleaves signal sequence
Discuss membrane asymmetry
- Membranes are different depending on their function
Discuss the influence of unsaturated fatty acids on membrane fluidity
- Produces a ‘kink’ and reduces packing
Discuss the influence of cholesterol on membrane fluidity
- Increases membrane fluidity (less packed)
- Decreases membrane fluidity (rigid sterol ring)
Describe the main features of the fluid mosaic model of membrane structure
- Lipid bilayer is dynamic, not static
- Proteins can be peripheral or integral and these can move too
Explain the restrictions on protein movement in the membrane, including potential interactions with cytoskeletal elements
- Aggregations, tethering, neighbouring cells
- Lipid-mediated (tend to be found in cholesterol-poor regions)
- Can be tethered to cytoskeletal elements, such as spectrin lattice dimers.
