Pathogens Pathogens are microorganisms that cause infectious disease.
Types of Pathogens
Bacteria
- Once inside the human body bacteria reproduce very rapidly.
- It then releases harmful chemicals called toxins.
- Toxins damage tissues and make us feel ill.
Viruses
- They can only reproduce inside a host cell.
- First the virus invades the host cell.
- It reproduces inside it.
- This is damaging to the cell, when the virus leaves the cell it can cause the cell to burst open and die.
Protists
- Protists are a group of microorganisms that have features that belong to animals, plants and fungi.
- Some are like animals, others more like plants and some, called moulds are closest to fungi.
- They are all eukaryotic.
Fungi
- Not all fungi cause disease.
- Not all fungi are single-celled. Some such as mushrooms are multicellular and so much larger. These are still made of tiny cells like yeast, but have many more of them.
- Fungal cells have a nucleus and so are eukaryotic.
- Yeast is a single-celled fungus that is economically important because we use it to make some bread and beer.
How Pathogens Spread
- Some are spread in airborne particles
- Some are spread in water
- Some can be spread through direct contact between individuals