PHGY 209 Lecture Notes - Lecture 5: Caveolae, Aquaporin, Sodium Chloride
18 Sep 2016
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Na+-glucose cotransporter: countertransport: when second solute moves in opposite direction to na, e. g. Endocytosis: membrane pinches off to form vesicle, engulfing sth. Exocytosis: vesicle inside of cell fuses with cell membrane, releasing contents into ecf: every exocytosis you lose some membrane, every endocytosis you gain some. Liquid contents inside slowly transferred to the cytosol. Membrane pinches off, forming phagosome with solid particle inside. Then this phagocytic vacuole fuses with lysosomes, degrading the material. Receptor-mediated endocytosis: clathrin-dependent: pinching off of clathrin-coated vesicles , which fuse w/ endosomes, where vesicle contents are sorted, potocytosis: clathrin-independent. Pinching off of tiny vesicles (called caveolae ), which deliver contents to cytoplasm via channels/carriers. Osmosis: diffusion of water across a semipermeable membrane (permeable to solvent but not to solute). Facilitated by aquaporins groups of proteins that form water permeable channels across cell membranes: osmotic pressure: pressure required to prevent the mvt of water, osmolarity: total solute concentration of a solution.
