The Caddyshack social coupling diagram, lecture part 12 (ΡΊ), from Libb Thims' 2015 "Zerotheism for Kids" lecture, illustrating coupled reactions in social terms, via the example of nepotism, from the 1980 film Caddyshack. |
“For a total process it is impossible to escape the rigorous requirement that the total free energy change, at constant pressure and temperature, must be negative if the process is to go. Such spontaneous processes (ΔG negative) have been termed ‘exergonic’ by Charles Coryell, in analogy to the term exothermic for processes in which ΔH is negative. A process which taken alone would be endergonic (ΔG positive), and therefore thermodynamically forbidden, may nevertheless proceed if it is coupled with another process which is so highly exergonic that the total value of ΔG for the combined reaction is negative. Such coupled reactions are of profound importance in biochemistry. The supply of free energy in many coupled biochemical reactions is provided by the hydrolysis of adenosine triphosphate (ATP to adenosine diphosphate (ADP) and inorganic phosphate.”— John Edsall (1958), Biophysical Chemistry [3]