Thermodynamics of Membrane Diffusion: Charged Ion

Practice: Calculate the free energy change (ΔG _transport) for the movement of Na ⁺ into a cell when its concentration outside is 150 mM and its cytosolic concentration is 10 mM. Assume that T = 20°C and ΔΨ = –50 mV (inside negative).

Practice: Calculate the ΔG_transport required to move 1 mole of Na ⁺ ions from inside the cell ([Na⁺] inside = 5 mM) to the outside of the cell ([Na ⁺] outside = 150 mM) when ΔΨ = –70 mV (inside negative) & the temperature is 37°C.

Practice: Calculate the ΔG_transport when Ca²⁺ ions move from the endoplasmic reticulum ([Ca²⁺] = 1 mM) to the cytoplasm ([Ca²⁺] = 0.1 μM). Assume that ΔΨ = 0 and T = 25°C.