Modeling cell energetics

Cells live in contexts with limited resources, and evolution has selected mechanisms that allow them to accomplish the tasks essential for life by making optimal use of the resources. This idea spans from one extreme of complexity of the cellular world (bacteria) to another (cancer cells), and is, in essence, the basis of constraint-based modeling, possibly the most successful approach for unraveling cell energetics. More or less recent work aimed at correlating energetics with thermodynamic and regulatory properties has brought to light a number of facts that are not explained by current theories. To make progress and understand whether evolution has found optimal solutions requires us to dig deeper into the space of possible states of a cell's metabolic network, and into the nature of the constraints that define it. We shall see how important hints derived from thermodynamical and regulatory considerations lead to novel insights and (possibly) entirely new classes of models, bearing a high potential for shedding light on the emergence of robust `growth laws' and for a more thorough understanding of what makes cell metabolism optimal.