Resting Membrane Potential — Cellular & General Physiology

Resting Membrane Potential MCQs: practice questions

Sample Resting Membrane Potential multiple-choice questions from Cellular & General Physiology.

1. A typical resting membrane potential of a nerve cell is approximately:

   • A. +65 mV
   • B. −70 mV
   • C. 0 mV
   • D. −15 mV
   • E. +120 mV

2. A membrane is permeable to K+ and Na+. Which ion will contribute more to resting Vm if its conductance is much higher?

   • A. The ion with lower conductance
   • B. The ion with higher conductance
   • C. Neither ion
   • D. Only Cl−
   • E. Only Ca2+

3. The Goldman equation differs from the Nernst equation because the Goldman equation considers:

   • A. Multiple ions and their relative permeabilities
   • B. Only one ion
   • C. Only ATP-dependent transport
   • D. Only extracellular concentrations
   • E. Only membrane thickness

4. In the Na+-selective setup above, side 1 becomes negative relative to side 2 because:

   • A. Cl− leaves side 1
   • B. Na+ accumulates on side 1
   • C. Water carries positive charge
   • D. ATP pumps negative charge into side 1
   • E. Na+ leaves side 1 without accompanying Cl−

5. A patient receives a substance that markedly increases Na+ conductance in an otherwise resting nerve membrane. Vm would tend to move:

   • A. Toward the Cl− equilibrium potential only
   • B. Toward EK
   • C. Toward −120 mV
   • D. Toward the resting value only
   • E. Toward ENa

6. A membrane potential becomes less negative when an inward positive-ion current exceeds outward positive-ion current. This change is called:

7. A decrease in extracellular K+ concentration would tend to make the resting membrane potential:

8. If an ion has no driving force across a membrane, net current through its channels is:

9. The driving force on an ion is determined by the difference between:

10. A larger concentration gradient for a permeant ion generally produces:

11. The Na+–K+ pump contributes to the resting membrane potential mainly by:

12. For Cl− diffusion through a Cl−-selective membrane from high to low concentration, the initially high-concentration side becomes:

13. A nerve cell has [Na+]i = 15 mM and [Na+]o = 150 mM. Its approximate Na+ equilibrium potential is:

14. If K+ channels are opened in a resting nerve cell, the membrane potential will tend to move:

15. At 37°C, the approximate equilibrium potential for K+ in nerve is:

16. A membrane is permeable to an ion, but its membrane potential equals that ion’s equilibrium potential. What is the net current?

17. If extracellular K+ concentration increases substantially while other factors are unchanged, EK becomes:

18. The resting membrane potential is conventionally expressed as:

19. A membrane is permeable to Na+ but not Cl−, with higher NaCl concentration on side 1. Initially, Na+ moves:

20. Which change would tend to shift the resting membrane potential toward EK?

21. The Na+–K+ pump is electrogenic because it normally:

22. Which statement about the direct voltage contribution of the Na+–K+ pump is most accurate?

23. If a membrane suddenly becomes much more permeable to Cl− and ECl is close to the resting potential, the membrane potential will tend to:

24. If a membrane becomes completely impermeable to K+ while remaining permeable to Na+, resting Vm would shift toward:

25. The Nernst equation is used primarily to calculate an ion’s:

26. Current flow across a membrane requires:

27. At electrochemical equilibrium for an ion:

28. At 37°C, the approximate equilibrium potential for Na+ in nerve is:

29. A diffusion potential can develop across a membrane only if:

30. Why is the nerve resting potential closer to EK than to ENa?