defence against disease

• What is a pathogen?

  A disease-causing organism, typically referring to viruses, bacteria, fungi, and protists.
• Which domain of organisms is not known to cause diseases in humans?

  Archaea
• What significant observations did Dr. Ignaz Semmelweis make regarding handwashing?

  Handwashing by surgeons significantly reduced the number of infections.
• What did Dr. John Snow's observations lead to in relation to cholera?

  Understanding that cholera is caused by a pathogen.
• How do skin and mucous membranes function as a primary defence against pathogens?

  They act as physical and chemical barriers preventing pathogens from entering the body.
• What do sebaceous glands in the skin secrete to prevent the growth of pathogenic bacteria?

  Lactic acid and fatty acids.
• What role do lysozyme enzymes play in the skin and mucous membranes?

  They kill bacteria by digesting the cell wall.
• What is the process of blood clotting designed to prevent?

  Loss of blood and entry of pathogens.
• What initiates the cascade of reactions in blood clotting?

  Release of clotting factors from damaged tissue and platelets.
• What is the role of thrombin in blood clotting?

  Thrombin converts soluble fibrinogen to insoluble fibrin.
• How does the innate immune system differ from the adaptive immune system?

  The innate immune system is non-specific and does not change, while the adaptive immune system is specific and builds memory.
• What are phagocytes and their role in the immune system?

  Phagocytes are white blood cells that engulf and digest pathogens.
• Where do lymphocytes circulate in the body?

  In the blood and lymph nodes.
• What triggers the production of antibodies in the adaptive immune system?

  Antigens stimulate the adaptive immune system to produce antibodies.
• What are the four different ABO blood groups determined by?

  The presence of antigens A or B on red blood cells.
• What happens if a person with blood type A receives blood from a type B donor?

  The immune system will produce antibodies against the B antigens.
• What is the role of helper T-lymphocytes in activating B-lymphocytes?

  Helper T-lymphocytes activate B-lymphocytes by recognizing and binding to antigens presented by phagocytes.
• What is clonal selection in the context of B-lymphocytes?

  Clonal selection is the process where activated B-cells divide to produce plasma cells that produce specific antibodies.
• What is the function of memory cells in the immune response?

  Memory cells ensure a rapid response if the same pathogen is encountered in the future.
• What is the consequence of HIV infection in lymphocytes?

  Infection of lymphocytes by HIV leads to AIDS.
• How do antibiotics function against bacteria?

  Antibiotics block processes occurring in bacteria but not in eukaryotic cells.
• What is herd immunity?

  Herd immunity is the protection of a population from disease when a sufficient proportion is immune.
• What are zoonoses?

  Zoonoses are infectious diseases that can transfer from other species to humans.
• What is the significance of evaluating data related to the COVID-19 pandemic?

  It helps understand the spread and control of the disease.
• What is the role of lysozyme in mucous membranes?

  Lysozyme enzymes kill bacteria by damaging their cell walls.
• What is the function of the immune system?

  The immune system defends the body against infection by pathogens.
• What is the difference between innate and adaptive immune responses?

  The innate immune response is non-specific, while the adaptive immune response is specific and builds memory.
• How do phagocytes recognize and engulf pathogens?

  Phagocytes recognize pathogens and engulf them by endocytosis.
• What is the role of macrophages in the immune system?

  Macrophages are involved in recognizing and engulfing pathogens.
• What happens to activated B-lymphocytes after they are stimulated?

  They undergo mitosis to produce plasma cells and memory cells.
• What is the significance of memory cells in the immune response?

  Memory cells provide a faster and more effective response upon re-exposure to the same pathogen.
• How do antibodies function in the immune response?

  Antibodies bind to specific antigens on pathogens to aid in their destruction.
• What is the role of helper T-lymphocytes in the immune response?

  Helper T-lymphocytes activate B-lymphocytes and enhance the immune response.
• What is the process of antibody production by B-lymphocytes?

  1. lymphocytes produce antibodies after being activated by helper T-lymphocytes and specific antigens.
• What is the role of the MHC protein in the immune response?

  The MHC protein presents antigens on the surface of phagocytes to activate T-lymphocytes.
• How do activated B-lymphocytes contribute to the immune response?

  Activated B-lymphocytes divide to form plasma cells that produce antibodies specific to the pathogen.
• What is the significance of clonal selection in the immune response?

  Clonal selection allows for the production of many identical plasma cells that produce the same antibody.
• What happens to plasma cells after they produce antibodies?

  Plasma cells continue to produce antibodies for a period before dying off.
• What is the role of antibodies in the immune system?

  Antibodies bind to specific antigens on pathogens to neutralize or mark them for destruction.
• How does the immune system remember past infections?

  The immune system retains memory cells that respond more effectively to previously encountered pathogens.