Topic 3-Infection and Response Flashcards
What are pathogens?
They are microorganisms that cause infectious disease. This includes, bacteria, protists and fungi
What is a communicable disease?
A disease caused by a pathogen which can be passed between animals or plants
How do viruses cause disease?
They move into cells and use the biochemistry of it to make many copies of itself
This leads to the cell bursting and releasing all of the copies into the bloodstream
The damage and the destruction of the cells makes the individual feel ill
How do bacteria cause disease?
They multiply very quickly through dividing by binary fission.
They produce toxins that can damage cells
What are fungi?
They can either be single celled or have a body made of hyphae
They can produce spores which can be spread to other organisms
How can pathogens be spread?
Direct contact- touching contaminated surfaces
By water-drinking or coming into contact with dirty water
By air-pathogens can be carried in the air and then breathed in
How can the damage that is caused by diseases be reduced?
- Improving hygiene (hand washing, using disinfectants, using tissues)
- Reducing contact with infected individuals
- Removing vectors (by using pesticides)
- Vaccination
Why is it especially important to prevent the spread of viral diseases?
Scientists have not yet developed cures for many viral diseases
What is measles and what are its symptoms?
Its a virus
Fever and red skin rash
Can lead to pneumonia, encephalitis (brain infection) and blindness
How is measles spread and prevented?
It is spread by droplet infection
It is prevented by vaccination at a young age
What is HIV and what are its symptoms?
Initially flu-like symptoms, then the virus attacks the immune system and leads to AIDS (body becomes susceptible to many different diseases)
How is HIV spread and prevented?
It is spread by sexual contact or exchange of bodily fluids such as blood
The spread is prevented by using condoms, not sharing needles, screening blood
Development of AIDS-use of antiretroviral drugs (stop replication of virus)
What is the tobacco mosaic virus and what are its symptoms?
A plant pathogen affecting many species of plants including tomatoes
Discolouration of leaves, the affected part of the leaf cannot photosynthesise resulting in the reduction of the yield
How is tobacco mosaic virus spread and prevented?
Contact between diseased plants and healthy plants, insects act as vectors
Good field hygiene and pest control
Growing TMV-resistant strains
What is salmonella food poisoning and what are its symptoms?
Bacteria that live in the gut of different animals, which we ingest when we eat the meat
Fever, stomach cramps, vomiting, diarrhoea
How is salmonella spread and prevented?
These bacteria can be found in raw meat and eggs, unhygienic condition
Poultry are vaccinated against Salmonella, keeping raw meat away from cooked food, avoid washing it, wash hands and surfaces when handling it, cook food thoroughly
What is gonorrhoea and what are its symptoms?
It is a bacteria
Thick yellow or green discharge from the vagina or penis, pain when urinating
How is gonorrhoea spread and prevented?
It is a sexually transmitted disease spread through unprotected sexual contact
By using contraception such as condoms and antibiotics (used to be treated with penicillin but many resistant strains are developing)
What is rose black spot and what are its symptoms?
Purple or black spots on leaves of rose plants, reduces the area of the leaf available for photosynthesis, leaves turn yellow and drop early
How is rose black spot spread and prevented?
The spores of the fungus are spread in water (rain) or by wind
By using fungicides or stripping the plant of affected leaves (have to be burnt)
What is malaria and what are its symptoms?
Caused by protist pathogens that enter red blood cells and damage them
Fevers and shaking (when the protists burst out of blood cells)
How is malaria spread and prevented?
The vector is the female Anopheles mosquito, in which the protists reproduce sexually. When the mosquito punctures the skin to feed on blood, the protists enter the human bloodstream via their saliva
Using insecticide coated insect nets while sleeping, removing stagnant water to prevent the vectors from breeding, travellers taking antimalarial drugs to kill parasites that enter the blood
How does the skin work to prevent pathogens from entering the body?
- Acts as a physical barrier
- Produces antimicrobial secretions to kill pathogens
- Good microorganisms known as skin flora complete with the bad microorganisms for space and nutrients