Infection and response

• Whats a pathogen?

  Microorganism, causing disease in body
• What do pathogens cause?

  Communicable disease
• Whats a communicable disease

  Easily spread
• What can be infected by pathogens?


  Plants and animals
• List 4 pathogens?

  Bacteria

  Viruses

  Protists

  Fungi
• What are bacteria?

  Small cells

  Make you feel ill, by producing toxins that damage your cells and tissues
• What are viruses?

  Not cells, tiny

  Reproduce rapidly

  Live inside cells & replicate, using cells' machinery to produce copies, cell will usually then burst, releasing new viruses

  Cell damage makes you feel ill
• What are protists?

  Eukaryotes & most are single-celled

  Some are parasites
• What are parasites?

  Live on/inside organisms and causes damage, transferred by vectors
• What are vectors?

  Carries and spreads the disease, not infected itself
• What are fungi?

  Some single-celled

  Others have a body (hyphae)

  Hyphae grows & penetrates human skin and surface of plants, causing disease. Can produce spores- spread to other plants & animals
• What are 3 viral diseases?

  Measles, HIV, Tobacco mosaic virus
• What are measles?

  Viral, spread by droplets of infected person's sneeze/cough

  People w/ virus develop red skin rash & show signs of fever

  Fatal w/ complications- sometimes lead to pneumonia or inflammation of brain (encephalitis)

  Most are vaccinated when young
• What is HIV?

  Virus, spread by sexual contact or by exchanging bodily fluids e.g. blood (from needles when taking drugs)

  Initially causes flu-like symptoms for few weeks, then no symptoms for several years

  Controlled with antiretroviral drugs

  Virus attacks immune cells

  If immune system is badly damaged, can't cope w/ infections or cancers. Known as late stage HIV infection or AIDS
• What do antiretroviral drugs do?

  Stop virus replicating in body
• What is the Tobacco mosaic virus?

  Virus, affects plants e.g. tomatoes

  Causes mosaic pattern- leave parts become discoloured

  Discolouration means plant cannot perform photosynthesis- affects growth
• Whats an example of a fungal disease?

  Rose black spot
• What is rose black spot?

  Fungus, causes purple/black spots to develop on rose plant leave's- leaves turn yellow and drop off, less photosynthesis happens- affects growth

  Spreads through environment in water/wind

  Gardeners treat using fungicides &stripping plant's affected leaves (these then need to be destroyed)
• What is an example of a disease caused by a protist?

  Malaria
• What is malaria?

  Part of life cycle takes place in vector (mosquito)- they pick up protist when feeding on infected person

  Every time it then feeds- it infects by inserting protist into animals' blood vessels

  Causes repeating fever- fatal

  Protected by mosquitos w/insecticides & mosquito nets
• What's two examples of bacterial diseases?


  Salmonella and gonorrhoea
• Whats salmonella?


  Bacteria causing food poisoning

  Fever, stomach cramps, vomiting and diarrhoea

  Get it through eating contaminated food

  In UK, most poultry given vaccination- controls the spread
• Whats gonorrhoea?

  STD

  Passed through unprotected sex

  Pain when urinating, yellow/green discharge from vagina/penis

  People use antibiotics to prevent pain/ or barrier methods like condoms
• How to reduce spread of disease?

  Hygienic- washing hands

  Destroying vectors- kill insects with insecticides or destroying habitat

  Isolating infected individuals- prevents from passing on

  Vaccination- less likely to pass on