# The design of unit cells by combining the self-reproduction systems and metabolic cushioning loads

## TL;DR

This paper explores how unit cells can be modeled by combining self-reproduction systems with cell cycle theory to better understand cell growth and optimize biotechnology applications.

## Contribution

The paper introduces a modeling framework that integrates self-reproduction processes with cell cycle theory to calculate unit cell properties and optimize productivity.

## Key findings

- The framework calculates physiological parameters like cell component numbers and flux patterns in unit cells.
- Cushioning components in unit cells regulate cell size and stabilize growth.
- Optimal productivity of cushioning components occurs at doubling times twice the minimal unit cell doubling time.

## Abstract

Recently, we published a comprehensive theoretical analysis of the self-reproduction processes in proto-cells (doubling of their components) composed of different combinations of cellular subsystems. In this paper, we extend the detailed analysis of structural and functional peculiarities of self-reproduction processes to unit cells of the Cooper-Helmstetter-Donachie cell cycle theory. We show that: 1. Our modelling framework allows to calculate physiological parameters (numbers of cell components, flux patterns, cellular composition, etc.) of unit cells, including also unit cell mass that determines the DNA replication initiation conditions. 2. Unit cells might have additional cell (cushioning) components that are responsible not only for carrying out various special functions, but also for regulating cell size and stabilizing the growth of cells. 3. The optimal productivity of the synthesis of cushioning components (useful cellular load) is observed at doubling time approximately two times longer than the minimal doubling time of the unit cells.

A modelling framework that combines cell self-reproduction processes with cell cycle theory allows to calculate unit cell’s detailed composition, numbers of cell components, flux patterns, unit cell mass, and optimal productivity for biotechnology.