Figure 2

A linear, nonequilibrium model of biological organization and dynamics. The SOFT-NET theory conceptualizes biological organization and dynamics in terms of nonequilibrium electron transport chains that support and, at the same time, are supported by electrons moving between redox centers along electron gradients. Electron flow/circulation is organized by and, at the same time, organizes intervening macromolecular media residing in an aqueous environment (see details in the text). Two major forms of electron transport and the corresponding organization of a linear electron transport chain are shown: A) fast electron transport through and by means of highly organized macromolecular media (e.g., proteins, lipids, nucleic acids, and their complexes) and B) relatively slow electron transport by means of the same disorganized chain components diffusing in the aqueous phase. Two consecutive "zoom-ins" (in A) reveal the multiscale complexity of alternative and, thus, competing pathways of electron flow. The apparent complexity is greatly simplified, however, by the fact that electron flow is organized in a self-similar (i.e., scale-invariant) manner, with pathways making up higher-order pathways making up yet higher-order pathways and so forth. Within each hierarchical level in the organization of electron flow, individual pathways are similarly clustered into families of related pathways, with the overall electron flow being dynamically, competitively, and highly unevenly partitioned among alternative pathways and pathway families. C) The model is brought closer to reality by introducing orthogonal flow of chain components passing through a steady-state organization of the electron transport chain. Filled (●) and empty (○) circles denote redox centers with excess and deficit of electrons, correspondingly. Dotted line (-·-·-·) denotes electron transfer. Geometrical shapes with complementary features are animate media.