Monod Biological Systems

Although several types of models have been explored in the description of biological systems, the unstructured black box continuum models based on a linear equation for substrate consumption are still most frequently used for the description of fermentation processes. In these models the growth rate of the cells generally is assumed to be a function of the external concentration of the growth-limiting substrate Cs according to Monod kinetics ... 

As Monod states in his treatise. On Symmetry and Function in Biological Systems, One may set aside the simple problem of fibrous proteins. Being used as scaffolding, shrouds or halyards, they fulfill these requirements by adopting relatively simple types of translational symmetries. Therefore, it was not anticipated that positive cooperativity, the effect Monod thought to be the second secret of life, second only to the structure of DNA, would be most beautifully demonstrated by designed variations of a repeating sequence of the mammalian elastic fiber based on translational symmetry. 

J. Monod, On Symmetry and Function in Biological Systems. In Nobel Symposium 11 Symmetry and Function of Biological Systems at the Macromolecular Level, A. Engstrom and B. Strandberg, Eds. Almqvist Wiksell Forlag AB, Stockholm, 1968, p. 1527. Also reprinted in Selected Papers in Molecular Biology by Jacques Monod, A. Lwoff, and A. Ullmann, Eds., Academic Press, New York, 1978, p. 708. 

Below the results of Sensitivity Runs with MADONNA are given from the BIOREACT example that is run as a batch fermenter system. This example involves Monod growth kinetics, as explained in Section 1.4. In this example, the sensitivity of biomass concentration X, substrate concentration S and product concentration to changes in the Monod kinetic parameter, Ks, was investigated. Qualitatively, it can be deduced that the sensitivity of the concentrations to Ks should increase as the concentration of S becomes low at the end of the batch. This is verified by the results in Fig. 2.30. The results in Fig. 2.31 give the sensitivity of biomass concentration X and substrate concentration S to another biological kinetic parameter, the yield coefficient Y, as defined in Section 1.4. 

Bottom-up systems biology does not rely that heavily on Omics. It predates top-down systems biology and it developed out of the endeavors associated with the construction of the first mathematical models of metabolism in the 1960s [10, 11], the development of enzyme kinetics [12-15], metabolic control analysis [16, 17], biochemical systems theory [18], nonequilibrium thermodynamics [6, 19, 20], and the pioneering work on emergent aspects of networks by researchers such as Jacob, Monod, and Koshland [21-23]. 

Analysis of the data for fundamental kinetic information was based on the Monod model. This model has been used by many successfully to describe the kinetics of biological waste treatment systems (26). The fundamental equation of this model is ... 

J. Monod, J.-P. Changeux, and E Jacob Allosteric proteins and cellular control systems. Journal of Molecular Biology 6, 306 (1963). 

Cohen and Monod (C2) have summarized experimental evidence which shows indeed that special mechanisms of transport of organic nutrients occur in bacteria. They call such transport systems permeases. This term ending in -use implies that the system involves enzymes—an implication not yet proved by available data. At any rate, it is found that permease systems can lead to transport against an apparent rise in concentration, as well as other effects not possible with Fickian diffusion. Various hypothetical mechanisms for operation of permease systems yield rates of permeation which exhibit the Michaelis-Menten type of dependence on substrate (including water) concentration. Perhaps it is in the occurrence of one of these mechanisms that the rate equation [Eq. (38)] assumed by Monod and almost all subsequent workers finds its justification. [For further information on biological transport, see, e.g., Christensen (Cl).]... 

---