On Parts and Wholes in Metabolism

Historically, the progress of science has been driven by its analytical approach. Although the biological sciences have been lagging somewhat behind the physical sciences, the last fifty years or so have seen an increasing avalanche in the identification and description of the components of living organisms. Refined instrumentation and ingenious techniques have gone hand in hand with sophisticated mathematical models of molecular properties. The method of choice has been to cut up the organism into ever smaller pieces and look at the pieces in ever greater detail. We can now detect a single specific nucleotide among millions and measure the presence of a few molecules in a whole cell. We can describe the dynamics of internal molecular motions and calculate the thermodynamics of their transitions.