Lecture 5

More thermodynamics

Coupling between reactions

The conservation of free energy available from biochemical processes occurs through coupling between reactions. The role of coupling, with examples from glycolysis, is discussed in detail here.

Making the equations more convenient

Because of the complexity of biochemical processes, the equations relating free energy to concentration of reactant can become unwieldy. In order to make the equations more useful, they are modified so as to refer to concentrations which can be readily assayed.

DGo' for ATP hydrolysis

The reaction of ATP hydrolysis provides an example of the use of the adjustments discussed in the paragraph above.

Oxidation reduction potentials

Examples of oxidation reduction reactions can be found in all major metabolic pathways, and dominate the oxidative metabolism of the mitochondria. Oxidation reduction potentials are important in thermodynamics because they provide a method for the direct measurement of the free energy available from a reaction. 

©Copyright 1996, Antony Crofts, University of Illinois at Urbana-Champaign, a-crofts@uiuc.edu