Neurons are electrically excitable cells. Their cell membranes can act as parall
ID: 1397973 • Letter: N
Question
Neurons are electrically excitable cells. Their cell membranes can act as parallel-plate capacitors and create a potential difference. In neurons, the typical resting membrane potential is approximately -68 mV. You have 1.07 x 106 Na+ ions on one side. Considering this system as a parallel-plate suggests that the other side has equal and opposite corresponding charge. Calculate the charge and capacitance of this biological capacitor.
The charge on the positive side of the membrane is: Coulombs
The capacitance is: Farad
Explanation / Answer
given,
potential of the membrane = -68 * 10^-3 V
number of Na+ ions = 1.07 * 10^6
since Na+ ions are having one extra proton so chrarge on one Na+ ion = charge of proton
charge on single Na+ ion = 1.602 × 10-19 coulombs
charge on 1.07 * 10^6 ions = 1.07 * 10^6 * 1.602 * 10^-19
charge on 1.07 * 10^6 ions = 1.714 * 10^-13 C
The charge on the positive side of the membrane is = 1.714 * 10^-13 C
capacitance = charge / potential
capacitance = 1.714 * 10^-13 / 68 * 10^-3
capacitance is = 2.521 * 10^-12 Farad