Concentrations of Ions inside and outside the cell [K+] inside: 120mM outside: 2

Question

Concentrations of Ions inside and outside the cell

[K+]     inside: 120mM        outside: 2mM

[Na+]   inside:8mM             outisde:150mM

A/ Resting membrane potential of a cell is largely governed by the fact that potassium channels are leaky and can be consdiered open. Thus, assuming potassium ions are in equilibrium across the membrane, calculate the resting membrane potential.

{for this one i only take into account the potassium outisde and inside. using the formular RT/zF ln ([Kout]/[Kin]) and got -.105V

B/ How much free energy per mole is released or does it take to pump sodium ion from the inside to the outside of the cell?

(for this one, using same formular i got potential Energy with Sodium is 0.0753V combine with answer in A and got total potential of 0.1803. So delta G is -34.8 kJ per mol)

C/ It take one mole of ATP hydrolyzing to ADP + Pi to pump three moles of sodium ions across the gradient. What is the intracellular ATP to ADP ratio given that [Pi]= 10mM and deltaG(knot) of ATP hydrolysis is -30kJ/mol?

(this one i am stuck and i get the ratio of 9.08E-12]

Can you please confirm the answers?

Explanation / Answer

A) Eeq,k = (RT/ZF) * ln ( [K+]out / [K+]in )
  R =  8.314 JK1mol1 ; T = 273 K ; Z = 1 ; F = 96,485 C mol1
Eeq,k = (8.314*273 / 1*96485) * ln ( 2/ 120)
Eeq,k = -0.09636 V
B) Eeq,Na = (8.314*273 / 1*96485) * ln (150/8)
   Eeq,Na = 0.06895 V
  G = 1 * 96485J V1mol1 *0.06895 V = 6652.64 J/mol

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