A network is a representation of a system of connected components. The network may be represented as a connected graph, a w:multi-graph, hypergraph, w:colored graph, meta-graph or category, and it has therefore a specific topological structure, or w:topology specified by the connections present between the system components. The behavior(s) of a network is (are), in general, distinct from that of its components, although it is ultimately determined by the interactions between its components. Whereas the network specifying a computer, an automaton, or a machine, or device, is decomposable into certain types of major subnetworks, such as group machines (clocks) and state-permutation modules, bionetworks of highly complex systems such as organisms are not decomposable in this sense into any simpler subnetworks or bio-modules without the loss of essential physiological functions that are characteristic to Life and living organisms.
- The w:genome of a cell can be represented by a genetic network which contains all the genes of the organisms that are functionally, or operationally, linked.
- The w:proteome of a cell is the network of all interacting proteins in a physiologically functional (living) cell.
- The w:neural network of a brain can be represented as a graph of all connected neurons in the brain.
- In the beginning, modeling of bionetworks was limited to random network models, and therefore one should carefully consider certain articles on `genetic networks'
to be only random models of the real genome, and therefore, perhaps only metaphors of the latter. similarly, initial models of brain networks that were called `neural networks' were random, and the term has also been extended to "artificial intelligence" (AI) networks that contain electronic circuits rather than real neurons of an organism.