Diffusion and Osmosis Lab – Flashcards
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Solute
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A substance that is dissolved in a solution.
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Solvent
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In a solution, the substance in which the solute dissolves.
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Solution
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A mixture that forms when one substance (the solvent) dissolves another (the solute).
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Selective permeability
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A property of a plasma membrane that allows some substances to cross more easily than others.
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Diffusion
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The passive movement of molecules from an area of higher concentration to an area of lower concentration.
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Facilitated diffusion
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The passive movement of specific molecules across a membrane, from high to low concentration, that is aided by transport proteins.
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Osmosis
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The diffusion of water across a selectively permeable membrane.
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Tonicity
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The ability of a solution to cause a cell to gain or lose water; it depends partly on the concentration of non-penetrating solutes relative to the inside of a cell.
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Isotonic solution
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A solution with the same concentration of water and solutes as inside a cell, resulting in the cell retaining its normal shape because there is no net movement of water.
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Hypotonic solution
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A solution with a solute concentration that is less than that inside the cell, which causes a net movement of water into the cell.
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Hypertonic solution
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A solution with a solute concentration that is greater than that inside the cell, which causes a net movement of water out of the cell.
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Hemolysis
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The destruction of red blood cells after exposure to a hypotonic solution, due to the gain of water through osmosis.
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Crenation
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The shriveling of a cell after exposure to a hypertonic solution, due to the loss of water through osmosis.
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Plasmolysis
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A phenomenon in plant cell in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water when exposed to a hypertonic environment.
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Active transport
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The movement of substances from an area of low concentration to an area of high concentration that uses energy provided by ATP or a difference in electrical charges across a cell membrane.
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What is the relationship between rate of diffusion and molecular weight?
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Lower molecular weight substances diffuse faster; Higher molecular weight substances diffuse slower.
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What does heating water do to the rate of diffusion of tea?
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Higher temperatures increase the rate of diffusion.
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What organs does the dialysis tubing represent?
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Kidney tubules, intestines
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Which solute diffused through the dialysis tube membrane - starch or glucose?
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Glucose
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Which solute did not diffuse through the dialysis tube membrane - starch or glucose?
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Starch
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How did we know that glucose diffused out of the dialysis tube membrane?
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Positive results of the Benedict's test when we tested the beaker water.
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How did we know that starch did not diffuse out of the dialysis tube membrane?
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Negative results of the Iodine test when we tested the beaker water.
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In which solution did the potato slices feel most turgid?
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Hypotonic
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In which solution did the potato slices feel most flaccid?
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Hypertonic
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Plant cells do best in _____ environments because their cells have the highest turgor pressure.
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Hypotonic
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Which of these solutions is isotonic to plant cells - 0.9% NaCl, tap water, or 10% NaCl?
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0.9% NaCl
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Which of these solutions is hypertonic to plant cells - 0.9% NaCl, tap water, or 10% NaCl?
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10% NaCl
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Which of these solutions is hypotonic to plant cells - 0.9% NaCl, tap water, or 10% NaCl?
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Tap water
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What happened to the central vacuole of the plant cell when exposed to a hypertonic environment?
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Water was lost from the central vacuole, causing the turgor pressure to drop. This resulted in plasmolysis as the plasma membrane contracted inwards, away from the cell wall.
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Which of these solutions more closely resembles the tonicity of blood plasma - 0.9% NaCl, tap water, or 10% NaCl?
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0.9% NaCl
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Which of these solutions will cause red blood cells to undergo crenation - 0.9% NaCl, tap water, or 10% NaCl?
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10% NaCl
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Which of these solutions will cause red blood cells to undergo hemolysis - 0.9% NaCl, tap water, or 10% NaCl?
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0.9% NaCl
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Brownian movement
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The intrinsic molecular kinetic energy that is the driving force of diffusion.
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Turgor pressure
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The pressure inside of a cell as the cytoplasm pushes itself against the cell wall due to the uptake of water.
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Osmolarity
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A measure of the total solute concentration per liter of solution.
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In more dilute concentrations of sucrose, the weight of the potato pieces _____ after incubation.
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Increases
