Applications of Chemical Kinetics in Environmental Systems - Elements of Environmental Engineering: Thermodynamics and Kinetics - page 379

ATP

Glucose

ADP

Glucose-6-phosphate

Fructose-6-phosphate ATP

ADP

Fructose-1,6-diphosphate

Glyceraldehyde-3-phosphate

Diphosphoglyceric acid

ATP

3-phospho-glyceric acid ADP

2-phospho-glyceric acid

Phosphoenol pyruvic acid

ATP

Pyruvic acid

ADP

FIGURE 6.64 Partial oxidation of glucose to pyruvic acid.

activity of microorganisms will be such that only those with negative overall free
energies will proceed spontaneously. Those with positive free energies will need
mediationbyATPandNAD-typecompounds.Aswehaveseen,biochemicalreactions
arethermodynamicallyfeasibleiftheoverallfreeenergychangeisnegative.However,
even if

G is negative, not all of the reactions will occur at appreciable rates to be of
any use in a living cell. The answer to this is catalysis caused by the enzymes present
in all living organisms. In Chapter 5, we derived the rate laws for enzyme catalysis.
In the following section, we will apply those expressions to study reactor design in
environmental engineering.

Δ