Gce Model Questions Vol1 2019 Biology Question 5

A cell maintains an intracellular potassium concentration of \(150\ \text{mM}\) and an extracellular concentration of \(5\ \text{mM}\). The membrane potential is \(-70\ \text{mV}\) (inside negative).\n(a) Calculate the equilibrium potential for K\(^+\) at \(25^{\circ}\text{C}\) using the Nernst equation.\n(b) State whether K\(^+\) would tend to move into or out of the cell spontaneously.\n(c) The Na\(^+\)/K\(^+\)‑ATPase moves 3 Na\(^+\) out and 2 K\(^+\) in per molecule of ATP hydrolysed. Assuming the standard free energy change for ATP hydrolysis is \(-30.5\ \text{kJ mol}^{-1}\), compute the net free‑energy change per mole of ATP when the pump moves the two K\(^+\) ions against their electrochemical gradient. Indicate if the pump can operate spontaneously.