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| Unit 2: Demos |
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VIDEO: The Diversity of Life (1c) Prokaryotes
v. eukaryotes How
do proteins maintain their positions in the lipid bilayer? Diffusion
demo - what's the difference between diffusion and osmosis? Cellular transport
processes Animal Tissues: |
The Extent of Osmosis The extent of osmosis is influenced by the difference in the number of solute particles per unit volume on the two sides of a membrane; the greater the difference, the more water will move from one side of a membrane to the other before equilibrium is reached. What is important is the total number of solute particles per unit volume - not the size or weight of the particles nor whether they are charged or uncharged—only the total number of particles is important. The total number of osmotically active (i.e., dissolved) solute particles per unit volume is referred to as the osmotic concentration. If there are several kinds of solutes in the same solution, as is invariably the case in living cells, then the osmotic concentration of that cell or solution is determined by the total (per unit volume) of all the particles of all kinds. If a dissolved substance separates into ions, each ion functions as a separate particle; for example, in determining the osmotic concentration of a saline solution, one dissolved molecule of sodium chloride (NaCl) is counted as two particles—one sodium ion (Na+) and one chloride ion (Cl-). As a result, a 1M solution of NaCl, which dissociates into ions, would have twice the osmotic concentration of a 1M solution of glucose, which dissolves but does not ionize. With this information you should be able to answer correctly the following problem from the Survival Manual:
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