Coupled biochemical reactions that act as sources of this quantity are modeled as Gerischer elements. The transepithelial form of this quantity is a common measure of tight junction barrier integrity. Gigaseals are omega-shaped regions of cell membranes for which this quantity is on the scale of 10^9 in SI units. The change in this quantity is proportional to cell volume in the mechanism of a Coulter counter. A sucrose gap creates a region where this quantity is high in an alternative to (*) patch clamping. The reciprocal of this quantity, written lowercase g, sometimes names the Hodgkin-Huxley model. Myelin increases this electrical quantity across the axolemma while decreasing capacitance, thus allowing for saltatory conduction. For 10 points, name this quantity equal to resistivity times thickness over cross-sectional area, or voltage over current. ■END■
ANSWER: electrical resistance [or impedance; accept resistivity before "resistivity"; prompt on conductance with “by measuring conductance, what other quantity are you also measuring?”; prompt on conductivity with “by measuring conductivity, what other quantity are you also measuring?; prompt on R; prompt on Z]
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= Average correct buzz position