#science/y9/disease
Pathogens §
- Pathogens are micro-organisms that cause communicable diseases when they enter the body.
- Not all micro-organisms are pathogens, some can be useful or neutral to the body.
- There are several different types of pathogen - these can infect animals or plants.
- Pathogens include bacteria, viruses, protists and fungi.
Bacteria §
- Bacteria are tiny cells which rapidly reproduce inside the body.
- Not all bacteria are harmful, but some are pathogens.
- They may make you feel ill by producing toxins which damage tissues.
- Examples of bacterial diseases include chlamydia, gonorrhoea, tuberculosis and salmonella.
Viruses §
- Viruses, unlike bacteria, are not living cells.
- They cannot reproduce by themselves, but more copies can be made inside your cells by using the cells’ machinery.
- They do this by taking over a cell, and forcing the cell to reproduce more copies of the virus.
- Cells then burst to release the new copies of the virus - this obviously damages cells.
Fungi §
- Fungi are things like yeasts and moulds - some fungi can be pathogens.
- They may have hyphae (thread-like structure) which penetrate plants and/or animals to cause disease.
- They can be spread by the production of spores.
Protists §
- Protists are eukaryotes, and most are single celled.
- Protists often get into an organism via a vector.
- A vector is an entity that carries the protist without getting infected itself.
- For example, malaria is caused by protists which are carried by mosquitos.