Sanjay Jain (University of Delhi; SFI External Professor)
Abstract. A class of mathematical models for the growth-division dynamics of a cell will be described. These models help in understanding several features of steady state bacterial cultures: (a) the origin of 'balanced growth' of chemicals in a cell, (b) the origin of cellular homeostasis, (c) the reason why chemicals grow exponentially in time in spite of their nonlinear dynamics, (d) the origin of the 'bacterial growth laws' of cellular composition (in particular the dependence of the ribosomal protein fraction on growth rate), and (e) how cells implement the 'adder' mechanism of size growth (in which cells add a constant size in each generation independent of their birth size). The simplicity of the models and the fact that they can be graded from the general to the particular allow us to pinpoint the model features that lead to the above properties, some shared by all bacteria and others specific to certain organisms.