TOPOLOGICALLY EQUIVALENT SPACES
Endoplasmic reticulum
Golgi Apparatus
Vesicles
Extracellular space
Membrane Synthesis
MEMBRANE SYNTHESIS
1. Phospholipids are synthesized on the cytosolic face of the ER and glycolipids on the lumenal face of the Golgi apparatus
2. Vesicles bud from organelles and transport them to cell membrane
3. Vesicles fuse with cell membrane the lipids they transport retain same orientation unequal distribution of molecules generates curvature
4. Flippases flip some phospholipids to the extracellular face of bilayer
5. Glycolipids remain on extracellular face (no flippase action)