Chapter 26, Problem 67MSPP

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.

If the investigator applies a 1.0 μA peak current at 40 kHz to a cell with twice the membrane area of the cell noted in the passage, what will be the peak out-of-phase voltage?

A. 0.32 V

B. 0.16 V

C. 0.080 V

D. 0.040 V