The spread of diseases

• Mitochondria are responsible for producing energy through respiration.
• Viruses


  Live and reproduce rapidly inside an organism's cells, which can damage or destroy the cells
• Viruses


  • measles
  • HIV (human immunodeficiency virus)
  • TMV (tobacco mosaic virus-plants)
• Spread of viruses


  1. Inhalation of droplets produced by infected people when sneezing and coughing

  2. Sexual contact

  3. Exchange of body fluids (e.g. blood when drug users share needles)

  4. Direct contact of plants with infected plant material

  5. Animal and plant vectors

  6. Soil the pathogen can remain in for decades
• Pathogens


  Microorganisms that cause disease
• Types of pathogens


  • Bacteria
  • Fungi
  • Protists
  • Viruses
• How pathogens can be spread

  1. In the air

  2. In water

  3. Through direct contact
• Pathogen


  Microorganism that causes disease
• Pathogens


  • Black spot (fungus)
  • Malaria (protist)
• Viruses


  Live and reproduce rapidly inside an organism's cells, which can damage or destroy the cells
• Viruses


  • measles
  • HIV (human immunodeficiency virus)
  • TMV (tobacco mosaic virus)
• TMV (tobacco mosaic virus)

  Infects plants
• TMV


  • Infects animals and plant vectors
  • Can remain in soil for decades
  • Destroys plants
  • Reduces plant's ability to photosynthesise, affecting growth
• Bacteria


  Reproduce rapidly inside organisms and may produce toxins that damage tissues and cause illness
• Salmonella


  Bacteria and the toxins they produce cause fever when ingested in or on food
• Gonorrhoea


  Sexually transmitted disease (STD) spread by direct sexual contact
• Plant diseases


  • Stunted growth
  • Spots on leaves
  • Areas of rot or decay
  • Growths
  • Malformed stems
  • Discolouration
  • Pest infestation
• Aphids


  Insect that sucks sap from plants, reducing rate of growth
• Ways to prevent spread of communicable diseases

  • Hygiene (hand washing, disinfecting, keeping raw meat separate, covering mouth when coughing/sneezing)
  • Isolation of infected individuals (people, animals, plants)
  • Controlling vectors (destroying or controlling population of vector)
  • Vaccination
• Plant diseases


  • AD
  • DO
  • events B
  • rens
  • mst
  • Fungi
  • Protists
  • malaria
• Fungi


  • Spread by water and wind
  • Cause rose black spot
• Protists


  • Cause malaria
  • Spread by mosquitos feeding on infected people and spreading the pathogen to others
• Organisms that spread disease by carrying pathogens between people are called vectors
• Ways of identifying plant diseases

  1. Gardening manuals and websites

  2. Laboratory testing of infected plants

  3. Testing kits containing monoclonal antibodies
• Plant defences


  • Physical barriers: Cellulose cell walls, tough waxy cuticle, bark
  • Chemical barriers: Antibacterial chemicals, poison production
  • Mechanical adaptations: Thorns, hairs, leaves that droop or curl
• Some plants mimic the appearance of unhealthy or poisonous plants to deter insects or herbivores
• 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, protist, 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 examples of viral diseases.

  measles,HIV, tobacco mosaic viruses
• Name two examples of bacterial diseases.

  salmonella, gonorrhea
• 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 caused 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 plants ability to photosynthesise.
• How can the cause of a plant disease be identified?

  gardening manuals and websites, laboratory testing monoclonal antibody kits.
• What’s are three mechanical defences that protect plants?

  thorns and hairs, leaves that droop or curl, mimicry to trick animals
• Give three physical defences of plants.

  cellulose cell walls, tough waxy cuticles, bark on tree