BIOL 2021 Lecture Notes - Lecture 10: Secretion, Cell Membrane, Clathrin
9 Feb 2017
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Particles and lfuid taken up from outside into the lysosome to get digested. Question: phagocytic cells such as macrophages engulf dead cells and even inert paricles like plastic beads. Why don"t they accidently engulf live cells: a: live cells have don"t eat me protein signals on their plamsa membranes that bind to inhibiting receptors on the macrophages dead cells lose these signals. Most (not all) pinocytosis uses clathrin coated vesicles. Fig 13-48 pinocytosis at plasma membrane using clathrin coated vesicles. In all eukaryotic cells, take up fluid and membrane. Called an endocytic-exocytic cycle (just as much goes out that comes in) Type of pinocytosis: receptor mediated endocytosis uses clathrin. Specific macromolecules taken up from extracellular fluid. Bind to transmembrane receptors collect in clathrin coated pits. Atherosclerosis = cholesterol deposits on artery walls. Or mutant receptor protein doesn"t enter pits. Some kinds of receptors actually get degraded in lysosomes (only make a one way trip) however this.
