The Complexity of Cell-Biological Systems

This describes the complexity of cell-biological systems that has an "inherent" basis, related to the nature of cells (large number and variety of components, nonlinear, spatio-temporal interactions, constant modification of the components) and arises also from the means one have for studying cells (technological and methodological limitations). It applies system theory to molecular and cell biology and seeks an understanding of structural and functional organization of the subcellular and macroscale level. The cell's functional organization at subcellular level can be grouped into three classes of processes: gene expression, metabolism, and cell signaling. This classification involves a range of technologies for each class, leading to an operational division. In systems theory, objects and relations between objects have identical ontological status. It also focuses on the cell's behavior (functionality) as a consequence of spatio-temporal interactions of molecules. At any level of an organism, its subsystems are interacting objects whose relationships and properties are largely determined by their function in the whole. While one can study a liver cell in isolation to investigate its stimulus-response behavior, one will only understand the cell's function fully by considering the cell and its environment as an undivided whole. The whole-part relationship emerges as a major stumbling block in dealing with the complexity of cell biological systems.