ABSTRACT
Modern cell biology aims at understanding the inner workings of cells. is is an ambitious goal given the f act t hat t he mole cular m achines t hat d rive c ellular re actions a re u nlike a ny c ounterpart i n t he macroscopic w orld. M olecular m achines re present s olutions to p roblems t hat a re not opt imized f or their e ciency or for the minimum number of components that industrial design guides necessarily would impose. Rather, they were assembled ad h oc from components that were a lready available and their de ning properties are robustness and adaptability, giving rise to properties like feed-back loops, cross talk, and redundancy (Coveney and Fowler, 2005; Ma’ayan and Iyengar, 2006). Furthermore, cellular machines can add, remove, and change their protein components, or reassign their function during full operation. ese speci cations complicate the identi cation of individual components and the relevance of their behaviors, i.e., cellular biochemistry, and the elucidation of the long-range causality of their actions down the chain of events to the desired e ect, i.e., cellular physiology.
