A European Informational Website
learn more
Many organisms consist of modules, both anatomically and in their metabolism. Anatomical modules are usually segments or organs. When we look at illustrations of metabolic reactions, we find that they, too, are modular: we can clearly identify, for instance, the citric acid cycle as a complex network that has only a few interfaces with other such modules. This principle holds true at various different scales: we can identify smaller modules within such larger networks that are similarly self-contained. We say that metabolic modularity is scale-free.