alga (plural algae)

Tiny, plant-like living things, usually freely floating. Algae have a green colouring and get energy from sunlight.

antibiotic

A chemical substance produced by a microbe that kills other microbes.

bacterium (plural bacteria)

A tiny, one-celled creature. Some give important benefits to people, while others are the main cause of infectious disease.

cell

The basic unit of all living things. Most microbes are made of just one cell.

diarrhoea

Very rapid movement of food through our insides. As a result, it comes out in a very watery form.

disease

A general word for an illness. However, the most common kind of diseases are those caught as a result of invasion by microbes.

energy

The ability to do work.

food poisoning

An illness brought about when food that contains a large number of bacteria is eaten. The bacteria release poisons as they break down the food.

fungus (plural fungi)

Usually a tiny, plant-like creature that lacks the green colouring of true plants and so is often white or grey.

germ

Any microbe that causes disease.

immunise

To protect against severe infection by giving a weakened dose of the infection.

infection, infectious disease

An invasion of the body by microbes. If the microbes cause illness as a result, it is called an infectious disease.

medicine

A chemical (drug) designed to help you get over some kinds of illness.

micro-organism

The long word for living things that can only be seen with the aid of a microscope.

microbe

A shortened word for micro-organism.

microscope

An instrument for looking at very small things.

parasite

A living thing that gets its food by living off another living thing.

plankton

Microbes that float about in oceans, rivers and lakes.

protozoan (plural protozoa)

Tiny, animal-like creatures. They are larger than bacteria and often eat bacteria.

virus

The smallest of the microbes and so simple that it is not truly a living thing on its own. It can only live in the cells of other living things.