Membrane Fluidity
MEMBRANE LIPID MOVEMENT
- Rotate
- Drift laterally
- Do NOT flip
- Degree of overlap
- Tail length
- Double bonds
- Transition temperature (Tm) determined by membrane composition
- Membrane phase changes as physiologic temp. fluctuate about Tm
- Temperature buffer that resists changed in fluidity
- Little overlap of phospholipid tails
- Longer/saturated tails
- Higher Tm
- No cholesterol
- Physiologic temperature ~ membrane Tm
- Cholesterol present
- An intermediate phase and most common physiologically
- Tails overlap
- Shorter/unsaturated tails
- Lower Tm
- No cholesterol