The reason why we call micro-organisms, micro-organisms is because they are small (we’re talking millionths of a metre or micrometers, which is represented by μm), and they forfill all the requirements of old MRS GREN[i] to be an organism. We’ll look at the two main ones in this book, which are, fungi[ii] and Bacteria[iii].                                                                                             

You may have read that micro-organisms have got much bad press since the discovery of germ theory -look at the number of hand washes and antibacterial soaps. It is true that these are responsible for a whole range of illnesses which previous to antibiotics (germ killing ninja warriors) caused so many fatal illnesses. 

This has spread the misconception that we should wipe micro-organisms off the face of the earth. However, these are fundamentally important for a whole host of things. Micro-organisms (yeast) is used to make alcohol, yeast is used to make bread rise and whether you like it or not they are in your body by the million. Ever heard the adverts that bang on about friendly bacteria? So, like so many sci-fi plot lines, you have the good guys and the bad guys.        

We’ll start by looking at Bacteria. Bacteria are:

·         Most often unicellular[iv] (made of only one cell)

·         Very small – a few micrometers (μm)

·         Can reproduce very quickly

·         There’s thousands of species

·         Incredibly adaptive, e.g. some have become resistant to antibiotics[v]

Fungi (for example yeast) are in some ways similar but have some differences also. They are:                                                            

·         Multicellular (more than one cell)

·         Far bigger than bacteria

·         Also known as mould

An interesting fact to do with fungi is that mushrooms are also fungi and we don’t see you throwing Dettol over them- or at least the non-poisonous ones.