Chapter 26, Problem 65MSPP

Cell Membrane Resistance

The capacitance of biological membranes is about 1.0 μF per cm² of membrane area, so investigators can determine the surface area of a cell membrane by using intracellular electrodes to measure the membrane’s capacitive reactance. An investigator applies a 1.0 μA peak current at 40 kHz to a cell and measures the peak out-of-phase voltage—that is, the component of the voltage due to the capacitive reactance of the cell membrane—to be 0.16 V.

What is the approximate capacitance of the cell membrane?

A. 20 × 10^–11 F

B. 10 × 10^–11 F

C. 5.0 × 10^–11 F

D. 2.5 × 10^–11 F