You are doing a measurement to determine the conductance of an artificial membra

Question

You are doing a measurement to determine the conductance of an artificial membrane. The membrane is selectively permeable to Na+. The temperature is 15 degrees C The external concentrate of Na+ is 500 mM The internal concentration of Na+ is 70 mM Using a voltage clamp apparatus you clamp the membrane voltage (Vm) at +20 mV At this clamped voltage you measure a current of -261 nA What is the membrane's conductance? Express your answer is "uS" (microSiemens) to 2 decimals and enter it into the answer box. Be sure to enter your units (us) in the units box. use the lower case letter 'u' to indicate mu, since it is easier to find on the keyboard. (E.g., 12.06us)

Explanation / Answer

Membrane potential = RT/nF ln [Cout/Cin]

                              = 1.98 cal * 288/ (1*2.3*10^4) ln [500/70]

                              = 0.048 V = 48 mV

Potential difference at the membrane = 20-48 = -28

membrane conductance = current/potential difference = -26.1 *10^-8 /-28 *10^-3V

                                                                                 =0.93 *10^-5 S

                                                                                  = 0.93 *10^-1 uS

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.