yulin week 1 - Diffusion and Osmosis Diffusion 1 A process...

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Diffusion and Osmosis Diffusion: 1. A process in which equilibrium is reached via random motions 2. Solutes always move from the more concentrated side to the less concentrated side Osmosis: Specifically the movement of water from where there`s more water to where there`s less water (=from where there`re less solutes to where there`re more solutes)
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Osmolarity and Tonicity Osmolarity 1. The measure of solute concentration per unit volume of solvent. 2. It takes into account ALL of the solute concentrations, not just the ones that cant cross the semipermeable membrane. Osmolarity=molarity (mol/L) * number of particles/molecule Tonicity 1. the measure of the osmotic pressure gradient between two solutions. 2. It is only influenced by solutes that cannot cross this semipermeable membrane, because these are the only solutes influencing the osmotic pressure gradient. One can have iso-osmolar solutions which are not isotonic
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What happens when cells are put into a hypertonic solution or a hypotonic solution? How to tell? 1. When a cell is in a hypertonic solution, meaning there`s more non-penetrating solutes outside attracting water, causing the cell to shrink. 2. When a cell is in a hypotonic solution, meaning there`s more non-penetrating solutes inside. Water flows in, and cell lyses. 3. Why not taking account into those penetrating solutes when talking about tonicity? It is because those solutes that can cross the membrane will eventually equilibrate, neither bringing water in nor out of the cell (in net).
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An artificial cell containing an aqueous solution of [0.04 M glucose, 0.01 M fructose, and 0.03 M sucrose] enclosed in a selectively permeable membrane was just immersed in a beaker containing a different aqueous solution: [0.02 M glucose, 0.05 M fructose, 0.01 M sucrose]. The volume of solution in the beaker is initially equal to the volume of solution inside the artificial cell. The membrane is permeable to water and monosaccharides (glucose, fructose,) but is completely impermeable to disaccharides (e.g. sucrose) . A. Which solute(s) will exhibit a net diffusion into the cell? Glucose Fructose Sucrose None B. Which solute(s) will exhibit a net diffusion out of the cell? Glucose Fructose Sucrose None C. In which direction will there be a net movement of water?
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