The K+ concentration inside a nerve cell is found to be 20xhigher outside the cell than inside the cell, while the Na+concentration is 20x higher inside versus outside. A. If themembrane potential Em (Ein-Eout) is -77.6 mV, identify the ion thatmust be transported actively versus the ion that is nearequilibrium (assuming ideal conditions). B. The NA+ -K+ -ATPase (orsodium-potassium pump), moves three sodium ions from inside tooutside, and two potassium ions from outside to inside whilesimultaneously hydrolyzing ATP to ADP + Pi. If ATP/ADP is 40 and[Pi] is 25mM, estimate the change in potential (∆µ kJ/mol) for thesodium transport, potassium transport and ATP to ADP + Piseparately (assuming ideal conditions). C. A researcher proposesthat perhaps a single ATP hydrolysis is sufficient for two roundsof Na+ /K+ exchange (i.e., move 6 Na+ atoms out and 4 K+ atoms in).Is the hydrolysis of a single ATP sufficient to account for theactive transport of ions for a single cycle? For two? Assume idealconditions & Justify your answer. D. Now imagine we are innon-ideal conditions, and the ionic strength on the inside of thecell is much higher than outside the cell. Considering only thesodium export, will this export be more or less favored whencompared to the ideal scenario (Justify your answer)
