It is a fact that bacteria grow bigger and faster when the nutrient’s quality become better. This principle is known as “growth law” in microbial physiology.
It describes the relation between the average bacterial cell size and the growth rate. But it is unable to explain the reason behind the constant maintenance of then cell size after reaching a particular critical size.
A team of bioengineers, biologists and physicists from the University of California, San Diego, has found the reason for this. They have also developed a “general growth law” which explains this.
They applied mathematical models to a lot of growth inhibition experiments on Escherichia coli. They observed that when cells started replicating their genetic material for the approaching cell division, the cell size stayed exceptionally constant, despite the several changes and genetic processes occurring inside.
This constant cell size indicates a basic unit of cellular resources needed to begin the cell cycle. This 'unit cell' is therefore the fundamental building block of cell size. And the sum of all constant unit cells for any growth condition, explains the growth law.
These findings have been published in the journal Current Biology.