Microorganisms - GCSE Biology Definition

Microorganisms are tiny organisms that are too small to be seen with the naked eye and can only be observed using a microscope. They include bacteria, fungi, and some types of algae and protozoa. Despite their small size, microorganisms have a significant impact on health, the environment, and many industrial processes. For example, they help to decompose dead material, aid digestion in our bodies, and are used in food production (e.g. yoghurt and bread). Some microorganisms can also act as pathogens, causing disease. Viruses, which can also be pathogens, are not microorganisms as they cannot carry out life processes on their own and are not considered living.