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28 Cards in this Set
- Front
- Back
All molecules display _____, or _____; this is why a dissolved molecule tends to move around in a solution.
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random thermal motion; kinetic energy
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Kinetic energy causes molecules to diffuse outward from regions of __________ to regions of __________.
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high concentration, heat, and pressure to regions of low concentration, heat, and pressure
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The net movement of molecules from high to low concentration continues until ____________.
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the distribution of molecules becomes homogenous throughout the solution
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Brownian movement
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the irregular motion of small particles suspended in a liquid or a gas, caused by the bombardment of the particles by molecules of the medium
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diffusion
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the passive, directional movement of molecules through solutions and across membranes in a predictable direction
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The direction of diffusion depends on _______ of _____, _____, and _____
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the presence of a gradient of concentration, heat, and pressure
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differentially permeable
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the ability of a cell to selectively communicate with its environment through its cellular membrane; it allows some molecules to pass while retarding others
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basic structure of membranes
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a two-layered core of nonpolar lipid molecules that selects against molecules not readily soluble in lipids
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polar molecules
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have positively charged areas and negatively charged areas
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nonpolar molecules
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have no local areas of positive or negative charge
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2 characteristics of molecules that governs their passive movement through a lipid membrane
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polarity and size
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dialysis
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the separation of dissolved substances by means of their unequal diffusion through a differentially permeable membrane
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phenolphthalein
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a pH indicator that turns red in basic solutions
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iodine
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a starch indicator that changes from yellow to dark blue in the presence of starch
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osmosis
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the diffusion of water across a differentially permeable membrane
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solution
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a homogenous, liquid mixture of two or more kinds of molecules
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solvent
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a fluid that dissolves substances
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solute
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a substance dissolved in a solution
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hypotonic
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a solution with a lower concentration of solutes, especially those solutes that do not pass across the surrounding membrane; water moves across semipermeable membranes out of hypotonic solutions
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hypertonic
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a solution with a high concentration of solutes
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isotonic
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refers to two solutions that have equal concentrations of solutes
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water potential
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the combined effects of concentration and pressure such as that from cell walls; water will flow from an area of high to low
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erythrocytes
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living red blood cells
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osmosis into animal cells ____________
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increases the hydrostatic (water) pressure and bursts the cells because they lack cell walls
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hemolysis
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the destruction of a red blood cell by the influx of water in a hypotonic solution
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lysis
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the destruction of a cell by the influx of water in a hypotonic solution
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crenation
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A process resulting from osmosis in which red blood cells, in a hypertonic solution, undergo shrinkage and acquire a notched or scalloped surface.
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plasmolysis
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the shrinking of the cytoplasm of a plant cell in response to diffusion of water out of the cell and into a hypertonic solution surrounding a cell
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