Systems Biology (Methods in Molecular Biology)

Chapter 9

Complexity of Biochemical and Genetic Responses Reduced

Using Simple Theoretical Models

Kumar Selvarajoo

Abstract

Living systems are known to behave in a complex and sometimes unpredictable manner. Humans, for a very
long time, have been intrigued by nature, and have attempted to understand biological processes and
mechanisms using numerous experimental and mathematical techniques. In this chapter, we will look at
simple theoretical models, using both linear and nonlinear differential equations, that realistically capture
complex biochemical and genetic responses of living cells. Even for cases where cellular behaviors are
stochastic, as for single-cell responses, randomness added to well-defined deterministic models has elegantly
been shown to be useful. The data collectively present evidence for further exploration of the self-
organizing rules and laws of living matter.

KeywordsSystems biology, Nonlinear dynamics, Biological networks, Oscillation, Modeling

1 Introduction

Recent estimates suggest that the human body consists of about

4 
 1013 cells across 200 cell types, covering different organs and

tissues. Within each cell, there are an estimated 20–25,000 genes,

and over 100,000 proteins and metabolites. These molecular spe-

cies, the fundamental building blocks of life, are connected through

a complex series of biochemical reaction networks that process

external information for survival and reproduction (Fig. 1)

[1]. For example, the food that an organism ingests is broken

down into various biochemicals, such as carbohydrates, proteins,

lipids, and nuclei acids through diverse reaction networks, either

spontaneously with binding partners or directed through catalytic

enzymes.

Aberrations to the highly robust biochemical networks, either

through genetic mutations or non-genetically through chronic

poor lifestyle habits, can lead to diseases and pre-mature death.

Thus, understanding the dynamic behaviors of various biochemical

networks is indispensable for biological research and good health,

Mariano Bizzarri (ed.),Systems Biology, Methods in Molecular Biology, vol. 1702,
https://doi.org/10.1007/978-1-4939-7456-6_9,©Springer Science+Business Media LLC 2018

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