Membrane Fluidity Flashcards
How do phospholipids move?
They can rotate or exchange in the lateral plane
They can also flip flop between leaflets but is v slow and rare
What does membrane fluidity depend on?
Presence of double bonds = unsaturated, increases fluidity
- Higher number of carbon atoms in tail makes it more rigid
How does cholesterol affect membrane fluidity and permeability?
No affect on fluidity
Makes membrane less permeable
Packs between phospholipids
Can prevent crystallisation
How do lipid anchored proteins attach to the membrane?
Via:
- A covalently bound fatty acid group
- Covalently bound prenyl group
- Phosphatidylinositol in outer leaflet
What are the advantages of lipid anchoring?
Mobility at cell surface
- Phospholipids move faster as 2D plane
Rapid release into EC space
What is transferrin?
Single-pass transmembrane protein
Receptor
Transmembrane domain usually alpha helix - high conc of hydrophobic AA
What forms a lipid raft?
Cholesterol and sphingolipids
What is a lipid raft?
Proteins floating in a sea of lipids
What roles do lipid rafts play?
Play a role in signalling and some forms of endocytosis
