4.1 Communicable Diseases (up to secondary defence) Flashcards
What is a pathogen?
A microorganism that causes disease
What are hyphae and mycelium?
Hyphae are clusters of cells in a fungus that grow in a branch-like design; mycelium are large groups of hyphae
Where do bacteria live in plants?
Vascular tissue
Where does fungus most often live in plants?
Vascular tissue
What are the four types of pathogen that we need to know?
Bacteria, viruses, fungi and protoctista
What diseases are caused by bacteria?
TB, bacterial meningitis, ring rot (potatoes and tomatoes)
What diseases are causes by viruses?
HIV/AIDS, influenza (animals), tobacco mosaic virus (plants)
What diseases are caused by fungi?
Black sigatoka (bananas), athletes foot, ringworm (cattle)
What diseases are caused by protoctista?
Malaria, potato/tomato late blight
What is direct transmission?
Passing a pathogen from host to new host, with no intermediary.
What is indirect transmission?
passing a pathogen from a host to a new host via a vector
What is transmission?
Passing a pathogen from an infected to uninfected individual
What is a vector?
An organism that carries a pathogen from one host to another.
What social factors affect transmission?
- Overcrowding
- Poor ventilation
- Poor health
- Poor diet
- Homelessness
- Being around people who have migrated from an area where a disease is more common.
What diseases are transmitted through direct physical contact?
HIV, bacterial meningitis, ringworm, athletes foot
What diseases spread through faecal-oral transmission?
Cholera, food poisoning
Which diseases are spread through droplet infection?
TB, influenza
Which diseases are transmitted by spores?
anthrax, tetanus
Where does plasmodium go after an infected person is bitten?
Their liver, then blood.
How do pathogens infect plants?
- Enter roots through soil (especially if damaged)
- Spores in airbourne transmission
How do plant pathogens spread?
Enter leaves which fall off or go into fruit and seeds so that all new plants will also be infected.
How does indirect transmission occur in plants?
Result of insect attack, transmit to other plants.
What is callose?
a large polysaccharide deposit that blocks old phloem sieve tubes at the end of growing season when not in use
What physical defences do plants have?
- Cellulose cell wall
- Lignin thickening of cell walls
- Waxy cuticles
- Bark
- Stomatal closure
- Callose
- Tylose formation