Term
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Definition
| each molecule continuously vibrates about an average position that tends to remain pretty well fixed with respect to the average position of neighboring centers of vibration. Long range order |
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Term
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Definition
| molecules have translational energy, i.e., the centers of vibration for each molecule are constantly flying about the container, and remain in no fixed position with respect to other centers of vibration. Very short range; dimension of one molecule. |
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Term
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Definition
| intermediate between solid and gas; liquid crystal domain, i.e., regions of a few molecules across where great order prevails, little crystals with molecular dimensions. Within a crystal domain, the centers of vibration of the molecules tend to be constant and we have a little molecular crystal. Short range; dimension of several molecules. |
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Term
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Definition
| a number which is proportional to the avg. kinetic energy of the molecules making up a body. Hence, temp. measures the avg. speed with which the molecules are moving about in a body. |
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Term
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Definition
| scale where zero point is condition of absolutely no molecular motion. Freezing point of pure water is 273K; increments are the same as the Celsius scale. |
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Term
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Definition
| has as its zero point the freezing point of water |
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Term
| k (universal Boltzmann's Constant) |
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Definition
| 1.3805*10^-16 erg/K; tells size things must be to have significant velocities. In avg. molecular velocity equation. |
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Term
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Definition
| amount of energy needed to move 1g, from rest, 1cm, in one second. (g cm^2/s^2) |
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Term
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Definition
rate at which the solute passes through a unit of cross sectional area. (J = mol/s*cm^2) Most important factor affecting flux is concentration of particles.
mobility term (D) * driving force (conc. Gradient or voltage gradient) |
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Term
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Definition
| moving from one side to other |
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Term
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Definition
| difference between 2 unidirectional fluxes (at equilibrium, = 0) |
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Term
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Definition
| of the amount of work that must be done to have the solute particle slip through its surrounding solvent molecules; characterizes the migration of particles of a given kind in a given medium at a given temp; surface area flux (J)/conc. gradient; cm^2/s |
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Term
P
permeability coefficient |
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Definition
| cm/s; use P when don’t know thickness of barrier; Permeability = diffusion coefficient (D)/barrier length (h) |
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Term
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Definition
| movement of solute particles w/ respect to its surrounding solvent molecules. Defined by driving force. (ex: electrophoresis) |
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Term
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Definition
movement w/ respect to the observer, of the solute particle together with its immediate environment. (ex: movement of molecules in water—osmotic swelling/shrinking)
(Convective flux = conc. * volume flow) |
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Term
| Mechanism of Permeation Type A |
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Definition
| diffusing through aqueous channels ex: diffusion thru membrane channels, channels controlled by a chemical, or channels controlled by a transmembrane voltage (passive) |
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Term
Mechanism of Permeation
Type B |
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Definition
dissolving through lipid phase
Ex: diffusion through lipid bilayer (passive) |
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Term
Mechanism of Permeation
Type C |
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Definition
| carrier mediated transport |
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Term
| Examples of carrier mediated transport |
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Definition
1) facilitated diffusion (passive)
2) active transport (active)(Na/K pump)
3) Symport (codiffusion) – usually tied to Na; links inward flux of Na to inward flux alanine against its conc. gradient; (passive) 4) Antiport (exchange diffusion)—moving Ca uphill as Na moves across passively (passive)
5) Bulk transport—endocytosis (outer part of cellular medium is engulfed and forms own vesicle |
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Term
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Definition
| measure in volts; electrical potential; proportional to the log of the ratio of ion conc across membrane. Use Nernst equation to calculate for potential of one ion—would also equal membrane potential if only one ion. |
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Term
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Definition
| use Goldman equation (leaves out z term and adds permeability) |
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Term
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Definition
| the passage of a potential from node to node of a nerve fiber, rather than along the membrane. |
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Term
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Definition
| energy of motion. (rotational, vibrational, translational) |
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