Disease and the immune system

• Define parasite?

  Lives in or on host

  Gains nutrition from host

  At the expenses of the hosts health
• How does a pathogen get into the plant and what type of molecules must be released?

  Through the cell wall and must release cellulase.
• Give an example of a protocista?

  Malaria and dysentery
• state a plant disease caused by bacteria?

  Ring Rot
• Bacteria and fungi in plants live in vascular tissue. Why?

  good supply water and nutrients, especially in phloem
• Name the infective agent that causes TB?

  Mycobacterium tuberculosis
• Name the parasite that causes malaria?

  Plasmodium
• Name the vector for the bacterial malaria parasite?

  Female Anopheles mosquito
• Name a human cell in which the malarial parasite reproduces?

  liver cell or red blood cell
• Describe characteristics of viruses?

  • Can only reproduce when in a host as they require the hosts DNA.
  • Viruses get inside your cells and interfere with the DNA.
  • Reproduces very rapiedly
  • HIV, Flu
• State characteristics of fungus?

  • Infect skin of organism
  • The hyphae grows under skin
  • They produce specialised reproductive hyphae and release spores
  • Athletes foot
• What is the direct method of transmission?

  Fecal transmission
• What is an indirect method of transmission?

  Vectors
• Suggest why erythrocytes that contain plasmodium are more likely to be destroyed by phagocytosis than healthy erythrocytes?

  Different chemicals that attract phagocytes (released from infected erythrocytes).
• What is a neutrophil?

  Most common phagocytic cell- ingests and digests pathogens and presents antigens to other cells of the immune system.
• What is a monocyte?


  Pre-cursor cell to the macrophage. Kindney shaped nucleus
• What are opsonins?


  Proteins that bind to antigens on pathogen, allowing phagocyte to bind.
• What do neutrophils have?

  lobed nucleus and granular cytoplasm
• Give two examples of autoimmune diseases?

  Rheumatoid arthritis, Type 1 diabetes, TB
• What type of cell is responsible for the rapid secondary response?

  T memory cells
• Describe how a secondary response can be caused artificially?

  The body‘s injected with dead or weakened vaccine. The complementary lymphocytes are activated by the T helper cells.
• What is an autoimmune disease?

  An autoimmune disease is a condition in which the immune system mistakenly attacks and damages the body's own tissues.
• What type of immunity is shown by antibodies passing to a baby through the mothers milk?

  Passive natural immunity
• How vaccinations can lead to immunity

  -Antigen is injected into the blood stream But there is no risk of infection

  An immune response is triggered

  -Specific B cells bind to the antigen, antigens are displayed

  -B cells are cloned to form plasma cells

  -Plasma cells produce antibodies that destroy the antigen

  -Some of the B cells become B Memory cells that remain in the blood and reproduces rapidly if the real pathogen infects.
• How is tuberculosis spread?

  Through the air In droplets
• What does MHC stand for?

  Major Histocompatibility Complex
• What does APC stand for?

  Antigen presenting cell
• What is the phagocytosis response of neutrophils?

  • The neutrophil picks up the chemicals secreted by pathogen.
  • Neutrophil arrives on site and engulfs the pathogen forming the phagosome.
  • Phagosome and lysosome fuse creating a phagolysosome which contains digestive enzymes which breaks down the pathogen
  • vesicles containing digested pathogen binds with plasma membrane and exocytosis occurs.
  • There are free radicals in lysosome which is hydrogen peroxide
• What do loads of neutrophils lead to?

  Pus
• What are opsonins?


  Antibodies or proteins that enhance phagocytosis.
• What is the role of cytokines?


  Cytokines attract phagocytes to the site of the infection by a process called chromotoxins.
• What do chitin cells walls belong to?

  Fungus
• What is herd immunity?


  Is when the vaccination of a significant proportion of the population provides protection for individuals who have not developed immunity.
• What is active immunity?


  Occurs when specific antibodies are produced by the individuals own immune system.
• What is passive immunity?


  Occurs when specific antibodies are introduced to the individual from an outside source.
• What’s an example of natural active immunity?

  Direct contact with pathogen
• What’s an example of natural passive immunity?


  Antibodies through breastmilk
• Is an example of artificial active immunity?

  Vaccination
• What is an example of artificial passive immunity?

  Injection of antibodies
• What are the function of B cells?

  Produce antibodies