Question

In the following scenarios, what is the EPC and EPP across the membrane?

a. large influx of Na+
b. Large influx of Na+ and small outflux of K+
c. Large influx of Na+ and large outflux of K+
d. Large outflux of K+

Answer 1

In the given scenarios, the EPC and EPP across the membrane depend on the movement of Na+ and K+ ions. A large influx of Na+ will create a positive EPP, while a large outflux of K+ will create a negative EPP.

Step-by-step explanation:

In the scenarios mentioned, the Electrochemical Potential (EPC) and Electrochemical Potential Gradient (EPP) across the membrane depend on the movement of sodium (Na+) and potassium (K+) ions.

1. Large influx of Na+: In this case, the EPC becomes positive outside the cell, creating a positive EPP across the membrane.
2. Large influx of Na+ and small outflux of K+: The EPC is positive, and the EPP will remain positive, but the magnitude may be reduced due to the small outflux of K+.
3. Large influx of Na+ and large outflux of K+: Here, the EPC remains positive outside the cell, while the EPP will be even more positive due to the large outflux of K+.
4. Large outflux of K+: In this scenario, the EPC becomes negative outside the cell, resulting in a negative EPP across the membrane.