Chapter 12- Communicable diseases Flashcards
(46 cards)
What are vectors?
Things that carry pathogens from one organism to another for example water or mosquitos.
What is a bacterial pathogen?
Prokaryotes
Infect eukaryotes
Classified by shape
No membrane bound nucleus or components
What basic shapes do bacteria have?
Rod shaped
Spherical
Comma
Corkscrew
What are the types of cell walls?
Two types with different structures and react differently to gram staining.
Gram positive bacteria look purple
Gram negative bacteria look red
The type of cell wall affects how bacteria reacts to different antibiotics
What are virus pathogens?
Non living infectious agents
Genetic material surrounded by a protein
Invades the cell and the genetic material takes over the cells biochemistry
Multiply rapidly in the host cell
What is a protoctista pathogen?
Eukaryotic organisms
Uses host cells
They need a vector to spread from one organism to the next
What are fungi pathogens?
Eukaryotic
Don’t photosynthesise
Digest food extracellularly
Often feed on dead matter
Stop the plant they attack from photosynthesising
How do viruses damage the host cell directly?
Take over the cell metabolism
Viral genetic material is inserted into the host cells DNA
Viruses multiply in the cell then burst out destroying it
How do protoctista damage the host tissues directly?
Some take over cells and break them open as the new generation emerge but do not take over the genetic material
They digest and use the cell contents as they reproduce
For example malaria
How do fungi damage the nhost cells directly?
Digest living cells and destroy them
How do bacteria produce toxins to damage host cells?
Produce toxins that poison or damage the host cells by breaking down cell membranes, some damage or inactivate enzymes and some interfere with the host cell’s genetic material to prevent them from dividing.
The toxins are a byproduct of the normal functioning of the bacteria
How do fungi produce toxins which damage host tissues directly?
Affects the host cells and causes disease
What is ringrot?
A bacterium disease in potatoes…
Caused by a gram positive bacteria
Damages leaves, tubers and fruit
No cure
What is Tobacco mosaic virus (TMV)
A virus that infects tobacco plants and other species
Damages leaves,flowers and fruit which means that growth is stunted and yields are reduced
Resistant crop strains are available but there’s no cure
What is potato blight?
Caused by a fungus like protocist oomycete
Penetrates host cells
Destroys leaves,tubers and fruit
No cure
Resistant strains, careful management and chemical treatments can reduce infection risk
What is black sigatoka?
A banana disease
Caused by a fungus
Attacks and destroys leaves
Penetrates and digests the cells
Resistant strains are being developed
Fungicide can control the spread
What pathogen is TB?
Bacterium called mycobacterium tuberculosis/ M. bovis
What does TB do?
Damages and destroys lung tissue and suppresses the immune system so the body is less able to fight off other diseases
What pathogen causes meningitis?
Bacteria
What does meningitis affect?
an infection of the meninges of the brain which can spread to the rest of the body causing septicaemia and rapid death. A rash develops
What is HIV?
A virus which targets T helper cells in the immune system of the body. It gradually kills the immune system so people are likely to contract other infections
What is HIV like?
Its a retrovirus with RNA as its genetic material. It contains the enzyme reverse transcriptase which transcribes the RNA to a single strand DNA to produce a single stand of DNA in the host cell. This DNA interacts with the genetic material of the host cell
What is the influenza pathogen?
A virus
What is influenza?
An infection of the ciliated epithelial cells in the gaseous exchange system. It kills them, leaving the airways open to secondary infection
