The spread of diseases

• What is a communicable disease?

  A disease that can be transmitted from one organism to another
• What is a pathogen?

  A microorganism that causes disease
• Name four types of pathogen


  Bacteria, Fungi, Protists, Viruses
• How can pathogens spread?

  Air, Water, Direct Contact
• How do bacteria make you ill?

  Produce toxins that damage tissues
• How do viruses make you ill?

  Reproduce rapidly inside cells, damaging or destroying them
• Name three types of viral diseases

  Measles, HIV, Tobacco Mosaic Virus
• Name two examples of bacterial diseases

  Salmonella, Gonorrhoea
• Name four methods of controlling the spread of communicable disease

  Good hygiene, Isolating infected individuals, Controlling vectors, Vaccination
• Describe an example of a protist disease

  Malaria - caused by a protist pathogen that is spread from person to person by mosquito bites, and causes recurrent fevers
• Describe an example of a fungal disease in plants

  Rose black spot - spread by water and wind, and affects plant growth by reducing a plant's ability to photosynthesise
• How can the cause of a plant disease be identified?

  Gardening manuals and websites, Laboratory testing, Monoclonal antibody kits
• What are three mechanical defences that protect plants?

  Thorns and hairs, Leaves that droop or curl, mimicry to trick animals
• What are three physical defences of plants

  Cellulose cell walls, Tough waxy cuticles, Bark on trees
• How can aphids be controlled by gardeners?

  Introduce ladybirds to eat the aphids
• How can plant diseases be detected?

  Areas of decay, Discolouration, Growths, Malformed Stems or Leaves, Presence of Pests, Spots on Leaves, and Stunted Growth