BIOL 200 Chapter Notes - Chapter 4: Epithelium, Transcytosis, Clathrin
Document Summary
Overview: three types of internalization of products from the cell surface: phagocytosis the ingestion of large particles by cells the particles are taken into phagosomes or food vacuoles. Occurs primarily in specialized cells e. g. macrophages, or protists such as amoeba or. Bacteria or other large particles are taken into membrane limited vesicles. Occurs in response to activation or cell-surface receptors. Results in the opening of calcium channels. Increase in internal [ca2+] triggers formation of a phagosome or food vacuole. May play an important role in removal of foreign organisms (bacteria) and in the scavenging of dead of damaged cells. Involves the uptake of macromolecules and fluid by cells. Formation of a vesicle containing the surface membrane with the attached molecules and the surrounded fluid. Substantial exocytic traffic to maintain cell size (constitutive secretory pathway!) May or may not use clathrin-coated pits to produce vesicles. Caveole (special type of vesicle) is sometimes used.