BIOL 141 Lecture Notes - Lecture 8: Endomembrane System, Endosome, Hydrolysis
Friday, October 20, 2017
BIOL 141
•Protein sorting pathway: secreted, membrane-bound, endomembrane organelles"
•Free ribosomes - cytosolic proteins, mitochondrial proteins, nuclear proteins"
•Lysosomes - found in animal cells, used for digestion and waste processing"
•Materials are delivered to lysosomes by three processes:"
•Autophagy - auto=self, phagy=eat"
•Phagocytosis - endocytosis is a process by which the cell membrane can pinch
off a vesicle to bring outside material into the cell, bringing something from outside
via endocytosis"
•Phagocyte - a type of cell, such as prokaryotic cell (bacteria) and cell fragments"
•Receptor-mediated endocytosis -vesicle from Golgi delivers hydrolyses, enzymes
within the lysosome catalyze hydrolysis reactions to breakdown macromolecules,
receptor indicates specific molecules (specific binding), receptors tend to be
membrane-bound proteins, ex: macromolecules in bulk"
•Endosome - some=bigger than a vesicle, has specific content"
•Pancreas cells secrete protein hormones"
•Secretory cells have complex endomembrane system, good model cell to study the
protein sorting pathway"
•Pulse-chase experiment"
•Baseline (control): non-manipulated condition"
•Pulse: ADD a label"
•label is removed or washed away"
•Chase: FOLLOW label over time"
•Labels are specific and quantifiable
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