Module 4: Biodiversity, Evolution & Disease

• What is active immunity?

  Resistance developed through the production of specific antibodies in response to a pathogen.
• How does active immunity provide long-lasting immunity?

  It produces memory cells that remain in the body.
• What are agglutinins?

  Chemicals that cause pathogens to aggregate together.
• How do antibodies function as agglutinins?

  They bind to pathogens, causing them to clump together for easier phagocytosis.
• What is an antibiotic?

  A chemical produced by a living organism that kills or prevents the growth of bacteria.
• What is antibiotic resistance?

  When bacteria mutate to survive and reproduce despite the presence of antibiotics.
• What are antibodies?

  Immunoglobulins produced by B-lymphocytes in response to a specific antigen.
• What triggers the immune response?

  The presence of a specific antigen on a pathogen.
• What is an antigen?

  A chemical present on the surface of a cell that induces an immune response.
• What is an antigen-presenting cell?

  A macrophage that displays foreign antigens.
• What are anti-toxins?

  Chemicals produced by white blood cells that neutralize toxins released by pathogens.
• What is artificial active immunity?

  The production of antibodies following exposure to a weakened or dead pathogen.
• How is artificial passive immunity acquired?

  Through the administration of specific antibodies from another organism.
• What is athlete’s foot?

  A form of ringworm in humans that affects the feet.
• What is an autoimmune disease?

  A condition where the immune system attacks healthy body tissue.
• What are bacteria?

  Prokaryotic cells that have cell walls but lack organelles.
• What is bacterial meningitis?

  A severe form of meningitis caused by bacterial infection of the meninges.
• What are B effector cells?

  A type of B lymphocyte that divides to form plasma cells.
• What is black sigatoka?

  A fungal disease in tomatoes caused by Mycosphaerella fijiensis.
• What are B lymphocytes?

  Lymphocytes that mature in the bone marrow and produce antibodies.
• What are B memory cells?

  B lymphocytes that provide immunological memory.
• What is callose?

  A plant polysaccharide that serves as a defense against pathogens.
• What are the main disease-causing pathogens in humans?

  Bacteria and viruses
• What are chitinases?


  Enzymes that degrade chitin in fungal cell walls.
• How do bacteria and viruses differ in terms of cellular structure?

  Bacteria are prokaryotic cells with no membrane-bound organelles, while viruses consist of nucleic acid enclosed in a protein coat
• What is clonal expansion?

  The mass proliferation of specific antibody-producing cells.
• What form does genetic information take in bacteria?

  A circular strand of DNA
• What is clonal selection?

  The identification of an antibody-producing cell with complementary receptors to a specific antigen.
• Why do bacteria not require a host to survive?

  Because they can live independently
• What is Clostridium difficile?

  A type of bacteria found in the gut that is resistant to most antibiotics.
• What is a key characteristic of viruses regarding their survival?

  Viruses are entirely dependent on their hosts
• What is a communicable disease?

  A disease caused by a pathogen transmitted directly between organisms.
• How do the sizes of bacteria and viruses compare?

  Viruses are significantly smaller than bacteria
• What are cytokines?

  Cell-signalling molecules produced by mast cells that attract white blood cells.
• What is direct transmission?

  The transfer of a pathogen directly from one organism to another.
• What structures do bacteria possess that viruses do not?

  Bacteria have a cell membrane, cell wall, cytoplasm, and organelles like ribosomes, plasmids, flagellum, and pili
• What bacterium causes tuberculosis (TB)?

  Mycobacterium tuberculosis
• What is an epidemic?

  A rapid rise in the incidence of a communicable disease at a local or national level.
• What are expulsive reflexes?

  Coughs or sneezes initiated upon irritation of the respiratory tract.
• How does TB initially affect the body?

  The first infection is symptomless as infected phagocytes are sealed in tubercles