Bacteria are living organisms. They come in different shapes and sizes but are only ever one cell. Bacteria reproduce asexually by dividing into two, to produce two bacteria genetically identical to the original. In the right conditions (usually warm, moist conditions), bacteria can reproduce every 20 minutes, which means if you start with one bacterium, in one hour you could have 8.
Bacteria live all over our skin and right through our alimentary canal. Most bacteria are harmless to us and some can even help us digest food. These ‘harmless’ bacteria can also help prevent harmful ones from having the opportunity to attack us.
To find out about bacteria in our mouths and on our skin, click through to the sections below.