An introduction to systems biology. Part II

Abstract

Enormous amounts of data and information on molecules that constitute the very complex cell machinery have been
collected, classified and stored in data banks. Although we posses such an enormous amount of knowledge about
the properties and functions of thousands of molecular entities, we are still far from understanding how they work
in a living cell. It is clear now that these molecules (genes, proteins) are not autonomous, that there is no direct linear
relation between genotype and phenotype, and that the majority of functions are carried and executed by concerted
molecular activity, and that the majority of diseases are multifactorial. A basic property of the matter in a living cell
(both normal and pathological) is an interaction between variety of macromolecules, mainly proteins, genes (DNA)
etc. In a process of self-organization they are able to form an active molecular biological system — a complex, labile
and dynamic network in which integrity is secured by non-covalent bounds. In this paper some basic properties of the
network structure and the universal rules that govern them are described. Network or systems biology is promising
new research approach in biology and medicine.