The four kinds of pathogen, the diseases you need for each, how they spread and how that spread is cut down.
What you will learn
- Tell communicable from non-communicable diseases
- Name the pathogen type behind each named disease
- Match each disease to how it spreads and how to control it
- Calculate bacterial numbers from a division time
Four kinds of pathogen
A pathogen is a microorganism that causes an infectious disease.
Diseases caused by pathogens are communicable: they pass from one person (or plant) to another. Heart disease or scurvy are non-communicable: nothing is caught.
- Bacteria reproduce quickly and may release toxins that damage tissues.
- Viruses are far smaller. They live and reproduce inside cells, damaging them.
- Fungi and protists cause disease in plants and animals too.
White blood cells fight pathogens, partly by making antibodies, proteins that stick to a pathogen (the next lesson explains how). Pathogens spread by air (droplets from coughs and sneezes), by water, by direct contact, and through vectors such as mosquitoes.
The rest of this lesson and its 11 practice questions are locked.
In this lesson
- Four kinds of pathogen
- The diseases you need
- How fast bacteria multiply
- Try it: Count the divisions
11 practice questions, marked as you go; about 20 minutes in all.
Key terms
Pathogen, Bacteria, Toxins, Viruses, Fungi, Protists, Antibodies, Vectors
In this unit: Infection and response
Pathogens and how they spread, the body's defences and the immune system, vaccines, antibiotics and resistance, drug trials, and (Biology only) monoclonal antibodies and plant disease.