Question: how does bactirea form

Samuel Ellis answered on 10 Mar 2015:

Bacteria are only a single cell, so unlike more complicated life like animals they don’t grow from anything (like an egg). Instead new bacteria are formed when older bacteria divide. A single bacterium will replicate it’s DNA so it has 2 copies, then the whole cell will split in half into 2 new identical ‘daughter’ cells. In this way the number of bacteria doubles.

As you can imagine, this doubling means lots of bacteria can form pretty fast. For example, the bacteria I work with are called E. coli, and they can divide around every 20 minutes when they are in their favourite conditions. This is useful for growing more of them, as we can put a small amount in an incubator overnight at their best temperature (37 degrees C, our body temperature) and have loads to use for experiments the next day!