Physicochemical Perspective of Biological Heterogeneity

Abstract

The vast majority of chemical processes that govern our lives occur within living cells. At the core of every life process, such as gene expression or metabolism, are chemical reactions that follow the fundamental laws of chemical kinetics and thermodynamics. Understanding these reactions and the factors that govern them is particularly important for the life sciences. The physicochemical environment inside cells, which can vary between cells and organisms, significantly impacts various biochemical reactions and increases the extent of population heterogeneity. This paper discusses using physical chemistry approaches for biological studies, including methods for studying reactions inside cells and monitoring their conditions. The potential for development in this field and possible new research areas are highlighted. By applying physical chemistry methodology to biochemistry in vivo, we may gain new insights into biology, potentially leading to new ways of controlling biochemical reactions.

Figure 1

There is a complex relationship between the cytoplasm’s and nucleoplasm’s physicochemical properties and the different levels of biological heterogeneity. (a) Life processes can be represented as equilibria, with reactions depending on the environment surrounding them. (b, c) Changes in temperature, ions, or macromolecules can alter this balance, favoring substrates or products. (d) In some cases, increased viscosity or steric restrictions can even prevent reactions from occurring. All of these effects (a-d) can occur in different compartments of the same cell. (e, f) Depending on the type of reaction affected, such as DNA processing or gene expression/metabolic pathways, slight changes in pH or temperature can result in phenotypic or genetic heterogeneity in a population of cells. (g) This, in turn, leads to further alterations in molecular composition and regulation of pH, ion concentrations, or temperature, which can further influence diversity in the outcomes of chemical reactions.