Use the information in the table to answer the question.

Calculate the equilibrium potential for potassium. Assume a temperature of 37°C.
A) +48.2 mV
B) 0.0 mV
C) -58.4 mV
D) -80.0 mV

Question

Use the information in the table to answer the question.

Calculate the equilibrium potential for potassium. Assume a temperature of 37°C.
A) +48.2 mV 
B) 0.0 mV 
C) -58.4 mV 
D) -80.0 mV

Quizplus · Accepted Answer

Using the Nernst equation: 
E = RT/zF * ln([K+]/[K+]) 
where R is the gas constant (8.314 J/mol*K), T is the temperature in Kelvin (37°C = 310 K), z is the charge (1 for potassium), F is the Faraday constant (96,485 C/mol), [K+] is the concentration of potassium (120 mM in this case), and [K+] is the concentration outside the cell (4 mM). Plugging in the values gives: 
E = (8.314 J/mol*K)(310 K)/(1)(96,485 C/mol) * ln(120/4) 
E = -58.4 mV, which is choice C.

Use the Information in the Table to Answer the Question