ABSTRACT
This chapter focuses on metabolism, specifically carbon and energy metabolism, meaning the processes by which a cell builds all of the molecules necessary to grow and divide. For example, E. coli's metabolic network enables each individual cell to create a nearly perfect copy of itself. This copy includes more than two million proteins, a DNA molecule over four and a half megabase pairs long, and specialized components like the cell membrane and the flagellum. Glycolysis is only one of the many pathways in the full E. coli metabolic network. Some of the pathways are mostly linear, such as the amino acid biosynthesis pathways; others are cyclic, such as energy-generating tricarboxylic acid cycle. By organizing reactions into pathways and building pathways into networks, Palsson's team constructed metabolic models of E. coli that became increasingly comprehensive. A substantial fraction of the reactions involve multiple reactants, and a handful of metabolites are involved in the lion's share of the reactions.
