This note from William Steinsmith, MD, belongs in Ripley’s Believe it or Not! It was accompanied by an underlined page from Nature on which “Big Bill” had made his computation.
The surface of the inner membrane of a mitochondrion is the venue of liberation of the free energy of the oxidation of glucose to water and carbon dioxide according to
6O2 + C6H12O6 —–> 6CO2 + 6H20 + 38 kcal per mole of glucose
The surface area of a mitochondrion’s outer membrane is about 9 x 10^ —12 square meters, whereas the surface area of the inner membrane is about 14,000 square meters. Hence, the inner membrane surface area is about 10^15 times as great as the outer membrane surface, i.e., a thousand trillion times as great.