Organisms That Cause Disease Flashcards
Define a pathogen.
A microorganism that causes disease.
What are the four main groups of pathogens?
Bacteria
Virus
Fungus
Protoctista
What is the organism called in which a pathogen lives?
The host.
How do pathogens live?
By taking nutrition from their host.
What kingdom do bacteria belong to?
Prokaryotae
How can the presence of bacteria affect the host?
Can cause disease by damaging cells or releasing waste products and / or toxins that can damage the host.
Where do bacteria often live in plants and why?
In the vascular tissue where they have easy access to nutrients.
What does bacteria do to plants?
Cause blackening and death of these tissues.
Where is fungus usually found in animals?
Under the skin.
How does fungus work in animals?
The fungus sends out reproductive hyphae which form a mycelium grow under the surface of the skin. The hyphae grow to the surface of the skin to release spores.
What does fungus cause in animals?
Redness and swelling at the surface of the skin.
Where does fungus usually live in plants?
The vascular tissue, where it can gain nutrients.
How is fungus spread in plants?
The hyphae release extracellular enzymes, such as cellulase, to digest the surrounding tissue, which causes decay.
What happens to plant leaves as a result of fungus?
Leaves will often become mottled in colour, curl up and shrivel before dying.
What happens to fruit and storage organs as a result of fungus?
They turn black and decay.
How do viruses replicate themselves?
Viruses invade cells and take over the genetic machinery and organelles of the cell. They then cause the cell to make more copies of the virus. The host cell eventually bursts, releasing many new viruses which will infect healthy cells.
How do Protoctista harm the host?
Protoctista usually cause harm by entering the cells and feeding on the contents as they grow.
What does the malarial parasite plasmodium feed on?
Haemoglobin in red blood cells.
Name three diseases caused by bacteria.
Tuberculosis
Bacterial meningitis
Ring rot (in plants)
Name three diseases caused by a virus.
HIV/AIDS
Influenza
Tobacco mosaic virus
Name three diseases caused by fungus.
Black sigatoka (bananas)
Ringworm (cattle)
Athlete’s foot (humans)
Name two diseases caused by a protoctista.
Blight (tomatoes and potatoes)
Malaria
What are the characteristics of malaria?
Parasite in the blood that causes headache and fever and may progress into a coma or death.
What are the characteristics of athlete’s foot?
Growth under skin of feet, particularly between the toes.
What are the characteristics of AIDS/HIV?
Attack cells in the immune system and compromise the immune response.
What are the characteristics of tuberculosis?
A disease that affects many parts of the body, killing the cells and the tissues; the lungs are most often affected.
