Why cells grow and divide? General growth mechanism and how it defines cells' growth, reproduction and metabolic properties

TL;DR

This paper introduces a general mathematical growth mechanism at the cellular level, explaining cell growth, division, and metabolic properties, validated by experiments on fission yeast and providing insights into fundamental biological questions.

Contribution

It presents a novel growth equation model that accurately predicts cell growth curves and links metabolic traits to cell size and evolution, surpassing previous models.

Findings

Analytical growth curve for fission yeast derived and validated against 85 experiments.

Fission yeast consumes 16-18 times more nutrients for maintenance than biomass.

The model explains why cells grow, divide, and how growth stops, addressing fundamental biological questions.

Abstract

We consider a general growth mechanism, which acts at cellular level and above (organs, systems and whole organisms). Using its mathematical representation, the growth equation, we study the growth and division mechanisms of amoeba and fission yeast Schizosaccharomyces pombe. We show how this mechanism, together with biomolecular machinery, governs growth and reproduction of cells, and these organisms in particular. This mechanism provides revealing answers to fundamental questions of biology, like why cells grow and divide, why and when cells' growth stops. It also sheds light on questions like why and how life originated and developed. Solving the growth equation, we obtain analytical expression for the growth curve of fission yeast as a function of geometrical characteristics and nutrient influxes for RNA and protein synthesis, and compare the computed growth curves with 85 experiments. Statistical evaluation shows that these growth curves correspond to experimental data significantly better than all previous approximations. Also, using the general growth mechanism, we show how metabolic characteristics of cells, their size and evolutionary traits relate, considering fission yeast. In particular, we found that fission yeast S. pombe consumes about 16-18 times more nutrients for maintenance needs than for biomass synthesis.