CELL MEMBRANE-TRANSPORT

SUMMARY

1. Exocytosis: vesicles containing material for export are targetted to the cell membrane via the v-SNARE/t-SNARE coupling mechanism. 2 pathways for secretion: non-constitutive pathway (proteins from the Golgi apparatus enter secretory granules to be processed) & constitutive pathway (proteins are transported directly to the cell membrane)

2. Endocytosis: via phagocytosis (cell-eating), pinocytosis (cell-drinking), clathrin-mediated endocytosis (occurs at membrane indentations where clathrin accumulates), caveolae-dependent uptake (occurs at membrane indentations where caveolin accumulates), non-clathrin/noncaveolae endocytosis

3. Small non-polar (O₂ & N₂) and uncharged polar-molecules (CO₂) diffuse freely across the membrane

4. Transport proteins

Reference(s)

Barrett, K.E., Barman, S.M., Brooks, H.L., X, J. and Ganong, W.F. (2019). Ganong’s review of medical physiology. 26th ed. New York: Mcgraw-Hill Education