In order to maintain the potential difference across the two sides of the membrane, cells carry ions across a membrane against the field ("uphill") using a variety of active transport mechanisms. one mechanism does so by using up some of the cell's stored energy converting atp to adp. how much work does it take to carry one sodium ion (charge = +e) across the membrane against the field? calculate your answer in ev/ion, joules/ion, and kilcalories/mole (the last for 1 mole of sodium ions).