If the pH of gastric juice is 1.2, what is the amount of energy (G) required for
ID: 977262 • Letter: I
Question
If the pH of gastric juice is 1.2, what is the amount of energy (G) required for the transport of hydrogen ions from cells lining the stomach (internal pH of of these cells equals 7.4) into the lumen of the stomach? Assume that the electrical potential difference across the membrane separating cytoplasm of these cells and the interior of the stomach is –70.0 mV (inside of cells negative relative to the lumen of the stomach). Assume that the temperature is 37 °C. The Faraday constant is 96.5 kJ·V–1·mol–1 and the gas constant is 8.314× 10–3 kJ·mol–1·K–1. Express your answer in kJ/mol.
Please show work :)
Explanation / Answer
dG = -RTlnK
R = gas constant
T = 37+273 = 310 K
pH = 7.4 ; [H+] = 3.98 x 10^-8 M
pH = 1.2 ; [H+] = 0.063 M
dG = -8.314 x 310 ln(0.063/3.98 x 10^-8)
= 36.795 kJ/mol
Is the energy needed for transport