communicable diseases

• What diseases do bacteria cause in plants and animals?

  Ring rot, TB
• What diseases do viruses cause in animals and plants?

  HIV/AIDS, Influenza, Tobacco mosaic virus
• What diseases do protoctista cause in animals and plants?

  Malaria, Potato/tomato late blight
• What diseases do fungi cause in animals and plants?

  Athletes foot, Black stigatoka
• What causes malaria?

  Female mosquito acts as a vector for protoctista
• What is a vector?

  An organism which carries a pathogen
• How are pathogens spread between animals directly?

  Through direct physical contact and droplet infection
• What are social factors affecting pathogen transmission in animals?

  Overcrowding, poor ventilation, poor health/diet
• How are pathogens spread between animals indirectly?

  Via a vector
• How are pathogens spread between plants directly?

  Fungi producing spores carried by the wind
• How are pathogens passed between plants indirectly?

  Insect carrying spores attacks plants
• In what type of climate do fungi and bacteria reproduce rapidly?

  Warm and moist
• How does the cellulose cell wall act as a physical defense?

  It acts as a barrier and activates chemicals
• How does lignin thickening cell walls act as a physical defense?

  It is waterproof and indigestible
• How does bark act as a physical defense?

  It contains chemicals
• How does stomatal closure act as a physical defense?

  prevents pathogens from entering
• How does callose act as a physical defense?

  Blocks flow in sieve tube to prevent spread
• How does tylose formation act as a physical defense?

  balloon-like swelling in the xylem and produces chemicals
• What are some types of active defenses in plants?

  • Thickened cell walls with cellulose
  • Callose deposition
  • Oxidative bursts producing reactive O2
  • Increased production of chemicals
• What are some chemical defenses in plants?

  • Phermones
  • Alkaloids
  • Hydrolytic enzymes
• Define necrosis and canker.

  Necrosis is deliberate cell suicide; canker is a lesion
• What are some primary defenses in animals?

  • Skin
  • Blood clotting
  • Expulsive reflexes
  • Mucous membranes
  • Inflammation
• Describe the method of blood clotting.

  Platelets release substances forming a fibrin network
• How does inflammation work?

  Histamine causes vasodilation and increases permeability
• Describe the mode of action of neutrophils (phagocytosis).

  Pathogen recognized by opsonin, engulfed via endocytosis
• What are macrophages?

  Antigen presenting cells that increase recognition
• Describe the mode of action of T-lymphocytes and B-lymphocytes in the specific immune response.

  Infection leads to antigen presentation and clonal expansion
• Why is the secondary immune response faster than the first?

  Memory cells are released at second infection
• Where are T-lymphocytes and B-lymphocytes produced?

  T: Thymus gland; B: Bone marrow
• What is an autoimmune disease?

  When the immune system attacks its own cells
• What is the function of T-regulatory cells?

  They prevent autoimmunity
• What are two examples of autoimmune diseases?

  Arthritis and lupus
• What is the structure and function of antibodies?

  • Variable region: specific to antigen
  • Constant region: same in all antibodies
  • 2 heavy chains and 2 light chains
  • Hinge region: provides flexibility
  • Disulfide bridges: hold chains together
• What are agglutinins?

  Antibodies that make pathogens stick together
• What are opsonins?

  Proteins that bind to antigens for recognition
• What are anti-toxins?

  Bind to molecules released by pathogens
• What is natural immunity?

  Immunity achieved through normal life processes
• What is passive immunity?

  Immunity from antibodies passed through breastfeeding
• What is active immunity?

  Immunity provided by our own antibodies
• What is artificial immunity?

  Immunity achieved through antibodies from vaccinations