Ken

“So, in summary, plants use the Gibbs free energy in sunlight to turn water and carbon dioxide into carbohydrates that contain some of the original solar free energy, while releasing oxygen. Animals access the Gibbs free energy trapped in carbohydrates to live and, by so doing, recombine the carbon in the carbohydrates with atmospheric oxygen to emit carbon dioxide and water. Scientists have now accounted for every single transfer of Gibbs free energy in all the chemical processes that occur in plants and animals and overall. A beautiful symmetry is at work here. Plants take in 2,870 kilojoules of solar free energy to make 180 grams of glucose (a typical carbohydrate). An animal that eats 180 grams of glucose releases exactly 2,870 kilojoules of free energy, eventually breathing out carbon dioxide.”
― Paul Sen, Einstein's Fridge: How the Difference Between Hot and Cold Explains the Universe