Prokaryotic cells which are 1/100 th the size of normal cells and can cause disease
They make you feel ill by producing toxins
These toxins cause cell and tissue damage
Makes you feel ill
E.g. Salmonella, gonorrhoea
They reproduce very quickly and split into two under the right conditions with the correct amount of nutrients every 20 minutes by binary fission
The rate of division of affected by
Oxygen levels
pH levels
Environmental conditions
They reproduce the best under moist, warm conditions
Viruses
They are not living cells and they are 1/100 th the size of a bacterium.
They consist of genetic material enclosed in a protein coating
They make you feel ill by invading your cells
They then use the cells machinery,chemicals, to replicate producing many copies of themselves
These copies break out of the cells releasing new viruses
Causes cell damage
Makes you feel ill
They can't reproduce on their own, they need a host cell
E.g. HIV, TMV, measles
Protists
Eukaryotes that are often unicellular which may cause disease
E.g. Malaria
Spread by animal vectors with carry the pathogen and transfer it to another organism which gets the disease
Often carried by parasites
E.g. Mosquitos
Fungi
They are unicellular or multicellular microorganisms which may cause disease
E.g. Athletes foot, rose black spot
They often have hyphae
Hyphae are thread like structures on the surface of a fungus
Hyphae spread the disease as they produce spores
Can be carried by air and water spreading the pathogen
Hyphae also spread disease by penetrating surfaces such as the skin of a human or the body of a plant
Spread of disease
Air
Fungal, bacterial and viral spores can be carried from one plant or animal to another in the air, spreading the disease
Droplet infection in humans is when you cough or sneeze and droplets containing infection are released and are then inhaled by others spreading the disease
E.g. Influenza
Some diseases can be spread by bring carried by the air and the inhaled
Wtaer
Direct contact
Some diseases can be spread by touching contaminated surfaces such as the skin