The membrane that surrounds a certain type of living cell has a surface area of
ID: 2150198 • Letter: T
Question
The membrane that surrounds a certain type of living cell has a surface area of 3.9*10 - 9 m2 and a thickness of 1.4*10 - 8 m. Assume that the membrane behaves like a parallel plate capacitor and has a dielectric constant of 4.1.(a) The potential on the outer surface of the membrane is + 59.7 mV greater than that on the inside surface. How much charge resides on the outer surface? (b) If the charge in part (a)is due to K ions(charge + e), how many such ions are present on the outer surface? Answer a1: the number of significant digits is set to 3; the tolerance is + / - 2% Answer b1: the number of significant digits is set to 3; the tolerance is + / - 2%Explanation / Answer
A = 3.9 x 10^(-9) m^2 d = 1.4 x 10^(-8) m Difference in V = 59.7 mV K = 4.1 C = K(?o)A(dV)/d = 6.032 x 10^(-13) C No of K+ ions = (6.032/1.602) x 10^6 = 3.767 x 10^6 ions