The second-law implications of biochemical energy conversion: exergy analysis of glucose and fatty-acid breakdown in the living cell

This paper gives the exergy analyses of the main stages of glucose and fatty-acid breakdown in living cells. Conversion processes like the glycolysis, the citric-acid cycle, and mitochondrial respiration consistently show exergy efficiencies of around or above 90%, while the membrane-transport processes are about 70-75% efficient. The overall efficiencies of glucose and palmitic-acid breakdown to activated phosphate groups in ATP are determined at 58% and 60%, respectively. Reasonable variations in the intracellular concentration data affect the efficiency results by no more than a few percentage points. The reported exergy analyses, thus, point at a high thermodynamic efficiency of living-cell energy conversion.