A model of cell growth dynamics

Abstract

A simple two-stage cell growth model accounts for many universal features of cell behavior. A cell is assumed to comprise two basic compartments, a synthetic one ( s) and a structural/genetic one ( n). A doubling of n is a necessary and sufficient condition for cell division, regardless of the state of s. It is argued that confirmation of a cell model based on single cell growth curves is of little value—that more sensitive tests can be obtained by studying simulated populations of the model cells. A population model based on the above assumptions shows a close similarity in dynamic behavior to that of actual cell populations. Phenomena accounted for include lag and stationary phases, increased cell size and changed chemical composition of cells at higher growth rates, absence of lag phase from inocula of rapidly growing cells, continuation of cell division after removal from nutrient, cell division response lag, and other dynamic and steady state properties including temperature effects. The possible chemical identities of the compartments are explored in the light of current experimental evidence. Shortcomings of the model are discussed.