Question

Which ion is most responsible for the resting membrane potential (RMP)?

• A. Potassium (K+)
• B. Calcium (Ca2+)
• C. Sodium (Na+)
• D. Chloride (Cl-)

Hint:

The resting membrane potential (RMP) is primarily maintained by potassium (K+) ions, with the Na+/K+ ATPase pump helping to maintain the ion gradient.

Answer 1

The Correct Option is A

The resting membrane potential (RMP) is primarily maintained by the differential distribution of potassium (K+) ions across the cell membrane. At rest, the inside of the cell is more negative compared to the outside, which is largely due to the higher concentration of potassium ions inside the cell and the relatively more positive extracellular environment. The Na+/K+ ATPase pump plays a critical role in maintaining this ion gradient by pumping 3 sodium ions out and 2 potassium ions in, helping maintain the negative resting membrane potential.
- Option (1) is correct as potassium (K+) is the key ion involved in maintaining the resting membrane potential.
- Option (2): Calcium (Ca2+) is important for signaling processes and muscle contraction but does not contribute significantly to the RMP.
- Option (3): Sodium (Na+) is involved in the action potential but does not significantly affect the RMP.
- Option (4): Chloride (Cl-) is involved in membrane potential but is not as central to the RMP as potassium.