Fig. 2

Cells could provide more than logic circuits. Computer science has developed models of computation that are far more powerful than combinatorial logic, such as finite-state machines or the Turing Machine. These models are more powerful in that they allow processing of a wider range of inputs into outputs, and in many more ways, than are admissible by combinatorial logic. Similarly, living systems have evolved a variety of computational processes to allow cells to process information. A simple model, used extensively as the basis for engineering combinatorial logic circuits in cells, is the standard representation of the central dogma (CD) of molecular biology. However, this model does not incorporate core cellular mechanisms such as metabolism, or processes such as evolution, which may provide possibilities for building more powerful, but as yet unknown, models