A typical cell membrane is 8.0 nm thick and has an electrical resistivity of 1.3 107 Ohms · m.

(a) If the potential difference between the inner and outer surfaces of a cell membrane is 80 mV, how much current flows through a square area of membrane 1.2 µm on a side?

A

(b) Suppose the thickness of the membrane is doubled, but the resistivity and potential difference remain the same. Does the current increase or decrease or remain the same?

By what factor?