The Membrane Bilayer Flashcards
1
Q
What are the general functions of biological membranes?
A
- Permeability Barrier (continuous, highly selective)
- Control of enclosed chemical environment
- Communication
- Recognition (signalling molecules)
- Adhesion proteins
- Immune surveillance - Signal generation (electrical, chemical) in response to stimulus
2
Q
How are phospholipids structured?
A
Head groups:
- Polar
- e.g. choline, amines, sugars, amino acids
Fatty acid chains:
- C14-C24 chains (C16 and C18 most common)
- Cis double bond = kink
3
Q
How are glycolipids structured?
A
Sugar containing lipids
CEREBROSIDES:
- head group SUGAR monomer
GANGLIOSIDES:
- head group oligosaccharide (sugar multimers)
4
Q
How are cholesterols structured?
A
- POLAR head group
- STEROID RING structure (rigid, planar)
- NON-POLAR HYDROCARBON tail
5
Q
What is the composition of the membrane (% dry weight)
A
- 60% Protein
- 40% Lipids
- 1-10% Carbohydrate
20% water as hydrated structure
6
Q
How may proteins move in bilayers?
A
- Conformational change
- Rotational
- Lateral
