4.1: Communicable diseases Flashcards
Define pathogen.
microorganisms that cause disease
4 different types of pathogens.
Bacteria, fungi, viruses and protoctista.
Name characteristics of bacteria.
Belong to kingdom Prokaryotae,
Reproduce rapidly (every 20 mins)
How do bacteria cause disease?
-Cause disease by releasing toxins that are toxic to the host.
Where does bacteria live in plants?
-Live in vascular tissues, and cause blackening and death of these tissues.
Name some diseases caused by bacteria.
-Tuberculosis
-Bacterial Meningitis
-Ring rot (In plants)
Characteristics of the disease tuberculosis
Affects many parts of the body, killing cells and tissues, lungs are most often affected
Specific organism that causes tuberculosis
Bacteria, M. bovis
Characteristics of bacterial meningitis.
Infection of the meninges (the membrane that surround the brain and spinal chord) May cause damage to brain and nerves.
Characteristics of ring rot (In plants).
Ring decay in the vascular tissue of a potato tuber or tomato accompanied by leaf wilting.
How does pathogen, fungi spread disease in animals?
-Fungus lives in skin of animal,
-Hyphae forms a mycelium which grows under surface of the skin
-Specialised reproductive hyphae at surface of skin release spores, leading to redness and irritation
How does pathogen, fungi spread disease in plants.
Lives in vascular tissue to gain nutrients,
-hyphae release extracellular enzymes
-these digest surrounding tissue
-causes mottling and curling up in plants
Name some diseases caused by fungi.
Black sigatoka in bananas,
Ring worm in cattle,
Athletes foot in humans.
Characteristics of black sigatoka
causes leaf spots on banana plants, reducing yield
characteristics of ring worm
growth of fungus in skin with spore cases erupting through skin to cause a rash.
characteristics of athletes foot
growth under skin of feet, particularly between the toes.
How do viruses cause disease?
Viruses invade cells, take over genetic machinery. They then cause the cell to manufacture more copies of the virus. The host cell eventually bursts, releasing many new viruses which will infect healthy cells.
Examples of diseases caused by viruses
HIV
Influenza
tobacco mosaic v
