communicable disease

• what are the categories of pathogen?

  bacteria, virus, fungi, protoctista
• what do bacteria lack that eukaryotic organisms have?

  membrane bound nucleus and organelles
• viruses are not living organisms
• are protoctista eukaryotic or prokaryotic?

  Eukaryotic
• are fungi eukaryotic or prokaryotic?

  Eukaryotic
• pathogen?

  microorganism that causes disease
• communicable disease?

  disease that can be passed from one organism to another
• what are the other names for protoctista?

  protists, protoctist
• what bacterial disease affects plants?

  ring rot
• what viral disease affects plants?

  tobacco mosaic virus
• what protoctista caused disease affects plants?

  potato late blight
• what fungal disease affects plants?

  black sigatoka
• why do viruses not have binomial names?

  not living
• what pathogen causes bacterial meningitis?

  bacteria
• what disease is caused by bacteria in animals?

  bacterial meningitis, tuberculosis
• what disease is caused by viruses in animals?

  HIV, AIDS, influenza
• what disease is caused by protoctista in animals?

  malaria
• what disease is caused by fungus in animals?

  athletes foot, ringworm
• the spread of disease through direct contact, inoculation, ingestion are all examples of direct transmission
• the spread of disease through fomites, droplets, vectors are examples of indirect transmission
• what is the name for inanimate objects that can transfer pathogens?

  fomites
• give an animal and non-animal example of a vector?

  mosquito, water
• what factors increase chance of contracting a communicable disease in animals?

  Overcrowding, poor sanitation, climate change, compromised immune system
• soil contamination and vectors are examples of indirect transmission
• what factors affect the transmission of disease in plants?


  overcrowding, climate change, genetic modification
• how can climate change impact spread of disease?

  flooding increases survival of waterborne pathogens, increased temperatures might encourage vectors to migrate
• how do bacteria reproduce?

  Binary fission
• why dont bacteria reproduce by mitosis?

  no nucleus
• what treats against bacteria?

  antibiotics
• when bacteria are cultured on a plate and antibiotic is added, the clearance area is called the zone of inhibition
• a parasite is an organism that lives in or on and harms host by feeding on the host
• inoculation - breaking the skin
• primary line of defence is non-specific
• examples of non-specific defense?

  skin, blood clots, mucous membrane, lysozymes, expulsive reflex, inflammation, phagocytosis
• Blood clotting and wound repair:

  · soluble fibrinogen gets converted to insoluble fibrin fibres

  · this forms a mesh that traps platelets when blood passes, eventually drying and forming a clot (scab if on outside)

  Provides a new barrier against pathogens while the skin underneath repairs itself
• Inflammatory response:

  Cytokines and histamines are released by mast cells(type of white blood cell found primarily at external surfaces (e.g. near skin, walls of organs, etc.))

  Histamines:

  Make blood vessels more ‘leaky’ to promote tissue fluid formation, causing swelling. more ‘leaky’ means more white blood cells, more tissue fluid around the area, so more inflammation. they cause blood vessels to dilate, increasing the temperature of the area (making it harder for pathogens to survive)

  Cytokines:

  Signal to phagocytes to gather and kill invading pathogens
• phagocytosis?

  Phagocytosis can trigger the specific immune response (i.e. production of antibodies) because some macrophages hold the antigens from the pathogens they destroy and ‘present’ them to the immune system antigen-presenting cells. In the cytoplasm of the macrophage, the antigen is combined with a glycoprotein - major histocompatibility complex. The MHC is then presented on the cell surface membrane. This activates other cells to produce an immune response.
• Phagocyte – specialised WBC which engulfs and destroys pathogens. They have lots of mitochondria and many lysosomes. Split into two categories: macrophages and neutrophils

  Phagosome – where the pathogen ends up within the phagocyte

  Phagolysosome – phagosome combined with lysosomes
• A chemical called opsonin helps this process. It binds to the antigen of a pathogen and then binds to the phagocyte.