Topic 4.1

• what is active immunity?

  Resistance in an organism that has developed through the production of specific antibodies in response to a pathogen. It provides long-lasting immunity as memory cells are produced
• what are agglutinins?

  Chemicals that cause pathogens to aggregate together, aiding phagocytosis.

  Antibodies can act as agglutinins.
• what is an antibiotic?

  A chemical or compound produced by a living organism that kills or prevents the

  growth of bacteria.
• What is antibiotic resistant bacteria?

  Bacteria that mutate to become resistant to an antibiotic,

  survive and reproduce very rapidly, passing on their antibiotic resistance.
• What are antibodies?

  Immunoglobulins produced by B-lymphocytes in response to a specific antigen, triggering an immune response.
• 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 neutralise toxins released by pathogens.
• what is artificial active immunity?

  The production of antibodies by the immune system following the

  exposure to a weakened, attenuated or dead pathogen
• What is artificial passive immunity?

  The immunity acquired from the administration of specific

  antibodies from another organism
• What is athlete's foot?

  A form of ringworm in humans that affects the feet, resulting in cracking and

  scaling of the skin.
• What is an auto-immune disease?

  A condition in which the immune system attacks and destroys

  healthy body tissue
• What are bacteria?

  Prokaryotic cells that have cell walls but lack organelles. Some bacteria are

  pathogenic, producing toxins that damage host cells.
• What is bacterial meningitis?

  A severe form of meningitis caused by bacterial infection of the meninges. Complications of bacterial meningitis include septicaemia
• What is a symptom of bacterial meningitis?

  When a rash of purple discolouration does not fade when a glass is pressed against it.
• 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, the hyphae of which penetrate and digest host leaf cells, turning them blac
• what are b lymphocytes?

  Lymphocytes that mature in the bone marrow. There are three main types; plasma cells, B effector cells and B memory cells.
• What are b memory cells?

  B lymphocytes that provide immunological memory
• what is callose?

  A plant polysaccharide that contains b -1,3 and b -1,6 linkages between glucose molecules.
• It is deposited between the cell walls and cell membrane in cells adjacent to Infected cells, serving as a defence against pathogens. It is also found in the cell walls of

  infected cells and the plasmodesmata between infected cells.
• What is chitinases?

  Enzymes that degrade chitin in fungal cell walls
• What is clonal expansion?

  The mass proliferation of specific antibody-producing cells
• What is clonal selection?

  The identification of an antibody-producing cell with complementary receptors to the shape of a specific antigen
• What is clostridium difficile?

  A type of bacteria found in the gut of some individuals which is

  resistant to most antibiotics.
• What is a communicable disease?

  A disease that is caused by a pathogen and transmitted directly between organisms.
• What are cytokines?

  Cell-signalling molecules produced by mast cells in damaged tissue. They attract

  white blood cells to the site of damage
• What is direct transmission?

  The transfer of a pathogen directly from one organism to another. This can occur via direct contact, ingestion or the sharing of contaminated needles.
• What is an epidemic?

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

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

  Eukaryotic, often multicellular organisms that may cause disease. They digest and

  destroy cells, and produce spores that can spread rapidly between organisms.
• What are glucananses?

  Enzymes produced by plants that decompose glucans, polysaccharides found in oomycete cell walls.
• What is a histamine?

  A chemical produced by mast cells in damaged tissue. It makes blood vessels dilate and causes their walls to become leakier.
• What is human immunodeficiency virus (HIV) ?

  An infectious virus that destroys T helper cells, weakening the immune system of the body
• What is indirect transmission?

  The transfer of a pathogen indirectly between organisms via fomites, vectors, droplet infection or soil contamination
• What is inflammation?

  A localised response of vascular tissue to pathogens, damage or irritants. It is characterised by pain, redness, heat and swelling
• What is influenza?

  A common viral infection caused by the family of viruses, Orthomyxoviridae, that destroys ciliated epithelial cells in the gaseous exchange system, exposing the airways to

  econdary infection.
• What are interleukins?

  Cytokines produced by T helper cells that stimulate B cells.
• What are lymphocytes?

  White blood cells that contribute to the specific immune response
• What is a lysosome?

  A membrane-bound organelle that contains hydrolytic enzymes.