BIO 203 Lecture Notes - Lecture 6: Blood Vessel, Electric Potential, Facilitated Diffusion
2 Nov 2016
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Document Summary
Water is always going to go from an area of low osmolarity to high osmolarity. Fresh water fish is hyperosmotic so water is always trying to flow into it, especially through the gills. Answer: drinks very little water, removal of h2o via kidney, urine. Salt h2o fish try to drink large amounts of water, absorb ions (actively) and. H2o (passively) across gut wall, at actively secrete ions across gills (oc urine=bfoc) Transport epithelial cells use vectored transport (move substances rom one membrane to another membrane) they have asymmetrical distribution of transporters within the cell. Epithelial cells are connected by tight junctions form an impermeable sheet. Abundant mitochondria to meet energy depend on ion transport. (active transport) Transcellular transport is dependent on transmembrane proteins, whereas paracellular transport is always passive down a concentration gradient. Transcellular transport: movement of solutes (or water) through epithelial cells. Paracellular transport: movement of solutes (or water) between adjacent cells.
