All life on Earth is made up of cells. We don't know how the simplest of those cells function.

The most complete computer simulation of a living cell has been created by a team at the University of Illinois. With this digital model biologists can explore how the most basic unit of life ticks and what would happen if it changed.

The senior author, Zaida (Zan) Luthey-Schulten, said that it would take many, many experiments to recover results from one simulation. Using the model, she and her colleagues have already made surprising discoveries about the physiology and reproductive cycle of their modeled cell, and the simulation continues to serve as an idea generator for further experiments.

Kate Adamala said that this is the first time that they can look into a metabolism of a whole complex system, not just a biochemical reaction or a very artificial system. It's hard to build a model if you don't know what.

The cell that the Illinois group is working with is so simple, with far fewer genes than any other cell, that it is an ideal platform for a model.

A lab-made cell teeters on the line between life and non life, carrying a limited number of genes, most of them necessary for survival. By replicating the biochemical processes happening inside this very basic cell and tracking all the nutrients, waste, gene products, and other molecule moving through it in three dimensions, the simulation brings scientists closer to understanding how the simplest life form sustains itself and reveals some of the bare-bones requirements of life.

Building models of natural cells that are more complex and significant is what the findings are about. Adamala said that if scientists could build an equally detailed simulation of the common intestinal bacterium Escherichia coli, it would be an absolute game-changer.

A digital life.

An updated version of a cell developed by synthetic biologists at the J. Craig Venter Institute was presented in Science in 2016 The project's scientists stripped genes that were not essential for life in order to design its genome. The JCVI-Syn3A has 493 genes, less than half of the number of genes that E. coli has.

The cell is simple, but not clear. No one knows what 94 genes do except that the cell dies. John Glass, leader of the synthetic biology group at the Venter Institute, said that their presence suggests that there may be living tasks or functions essential for life. The researchers hope that with modeling they can quickly uncover some of the mysteries.