Introduction to Metabolism

Molecules organize forming cells, but cells are not simple mixtures or assemblies of molecules. If thrown to a test tube separately or in a random mixture, the whole set of molecules of a cell would interact physically and react chemically but would not spontaneously form a cell. Cells form and exist because the molecular events that create and maintain cells are highly ordered. The sequence and specific place of events and the flows of matter and energy are such that the cell is able to preserve stability and evolve by adaptation to a certain extent, as addressed in Sect. 1.1. In Part II, we will focus on some of the most important chemical reactions occurring in different tissues of the human body and their coordination so that one understands how the changes of matter and transfer of energy enable the human body to exist, move, adapt to external challenges, and reproduce. This ensemble of chemical reactions is called metabolism.