For a typical vertebrate cell the transmembrane potential is about -70 mv (inside negative). the concentration of na+ inside the cell is 12 mm, and that in the blood plasma is 145 mm. what is the free-energy change for transporting 1 mole of na+ out of the cell to the blood at 37 c? assuming this sodium gradient is coupled to the transport of glucose by a na+ glucose transporter, which transport 1 mole of glucose inside the cell along with 2 moles of na+ ion. what is the maximum glucose gradient can the na+ transporter work against?