Keywords: exergy analysis, exergy efficiency, biochemical energy conversion, living cells, glycolysis, citric acid cycle, mitochondrial respiration, mitochondrion, glucose breakdown, fatty acid breakdown, palmitate, second law of thermodynamics, fatty acids, thermodynamic efficiency
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.