Why do cells divide? Why don’t cells get bigger and bigger? Nerve cells are massive and still work. Fat cells are also massive. It’s all about connectivity, efficiency, and identity.

A human being is roughly an assortment of 3.7±0.8×10¹³ cells or 37,000,000,000,000 which is a big number. But why so many?

Bacteria are tiny tiny. known bacteria falling somewhere between 0.4 and 2 μm in diameter and 0.5 and 5 μm in length (though many grow as filaments that can be tens or hundreds of times this long). A mou metre is 1,000,000 of a metre or 0.001 of a millimetre. Humans can see to about 0.1mm about a human hair. Anything smaller and we need help.

https://bmcbiol.biomedcentral.com/articles/10.1186/1741-7007-10-101

http://book.bionumbers.org/how-big-is-a-human-cell/

Bacterial cell –

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4399329/#!po=0.632911