3.2 - Communicable Disease (Viruses)

• Viruses aren’t cells and aren’t living but are still classed as organisms
• 10,000x smaller than animal cells
• Viruses cannot reproduce by themselves
• Viruses get into our cells and use them to reproduce, then they burst the cell and those new copies of the virus then infect other cells in our body
• Damages our bodies from the bursting of cells
• Measles

  Infected person coughs or sneezes

  • red rash across body
  • fever
  • can be fatal
  • vaccination available
• HIV (Human Immunodeficiency Virus)

  Spread by sexual contact

  Exchanging bodily fluids

  • inadequate immune system
  • flu-like symptoms
  • unusual infections - AIDS
  • cancers - AIDS
  • antiretroviral drugs (prevent virus from replicating)
• Tobacco Mosaic Virus (Plant Disease)

  Direct contact

  • discolours patches on leaves causing a mosaic pattern
  • photosynthesis can’t take place