Question

This table below provides approximate values for the intracellular and extracellular concentrations in unit mmol/L for sodium, potassium, and chlorine ions in a frog muscle with a resting potential difference of −98 mV and for the squid axon with a resting potential difference of −70 mV. Calculate the equilibrium potential difference (in mV) for each ion species in both cases at 17°C.

Table:

Frog muscle (intracellular, extracellular)

Na+ = 9-13, 120

K+ = 140, 2.5

Cl- = 3.5, 120

Squid Axon (intracellular, extracellular)

Na+ = 50, 440

K+ = 400, 20

Cl- = 40-100, 560

Answer 1

Using this formula we calculate the equilibrium potential as follows:
For frog muscles
Na ion = 59.7mV
K ion = -100.6mV
Cl ion = 88.3mV
The potential differnce for frog muscles:
Na ion = -157.7mV
K ion = 2.6mV
Cl ion = -186.4mV
Equlibrium potential for Squid Axon
Na ion = 54.33mV
K ion = -73.28mV
Cl ion = 51.9mV
the potential difference for the squid axon:
Na ion = -124.4mV
K ion = 4.9mV
Cl ion = -121.9mV