Question

Intestinal epithelial cells pump glucose into the cell against its concentration gradient using the Na⁺-glucose symporter. Recall that the Na⁺ concentration is significantly higher outside the cell than inside the cell. The symporter couples the "downhill" transport of two Na⁺ ions into the cell to the "uphill" transport of glucose into the cell.

 If the  Na⁺ concentration outside the cell ([ Na⁺ ]_out) is 149 mM and that inside the cell ([ Na⁺ ]in) is 23.0 mM, and the cell potential is -50.0 mV (inside negative), calculate the maximum energy available for pumping a mole of glucose into the cell. Assume the temperature is 37 °C. 

What is the maximum ratio of [glucose]_in to [glucose]_out that could theoretically be produced if the energy coupling mol were 100% efficient? 

Answer 1