Immune system

• What is a lymphocyte?


  Type of white blood cell involved in defence mechanism responses
• How do lymphocytes identify foreign cells?


  Each type of cell has specific molecules on its surface
• What are the most important molecules for lymphocytes in identifying foreign cells?


  Proteins
• What are the two types of defence mechanisms?

  Specific and non-specific
• How does the specific defence mechanism differ from the non-specific defence mechanism?


  Specific response is slower and tailored to each pathogen
• What are examples of non-specific defences?


  Physical barriers like skin and phagocytosis
• What are examples of specific defences?

  Cell mediated response and humoral response
• What type of white blood cell is involved in phagocytosis?


  Phagocytes
• What is a pathogen?


  Organism that causes disease
• What happens during phagocytosis?


  A pathogen is recognized and engulfed by a phagocyte
• What is the role of lysosomes during phagocytosis?


  Lysosomes fuse with the phagosome to release digestive enzymes
• What are antigens?


  Molecules that generate an immune response
• What are T cells involved in?


  Cell mediated immunity
• What is the process of cell mediated immunity?


  Phagocytes present antigens to T cells, which then activate immune responses
• What do cytotoxic T cells produce to kill infected cells?


  A protein called perforin
• What is the purpose of memory cells?


  To provide a faster and longer response to the same antigen
• Describe the process of the humoral response.


  B cells produce antibodies after binding to antigens on pathogens
• What is antigenic variability?


  When antigens on a pathogen change frequently due to genetic mutations
• What are antibodies?


  Proteins with specific binding sites complementary to specific antigens
• Describe the structure of antibodies.


  Quaternary protein with four polypeptide chains: two heavy and two light
• What are some roles of antigens?


  Coat pathogens, agglutinate bacteria, immobilize bacteria, and neutralize toxins
• What are monoclonal antibodies?


  Antibodies made in labs specific to antibodies
• How do pregnancy tests work?

  They detect HCG hormone in urine using antibodies
• What are some ethical concerns regarding monoclonal antibodies?


  Involvement of mice in production and potential side effects
• What do direct ELISA tests test for?


  Presence of a specific antigen in a patient
• How does a direct ELISA test work?


  Antigen binds to the plate, and a complementary antibody is added
• How does an indirect ELISA test work?


  Specific antigen binds to the plate, and patient sample is added to detect antibodies
• What is passive immunity?


  Immunity acquired through the transfer of antibodies from one individual to another
• What is active immunity?


  Immunity acquired through the production of antibodies in response to infection or vaccination
• What is a vaccination?


  Introducing antigens of a disease to stimulate antibody production
• What are features of a successful vaccination program?


  Economically available, few side effects, and can provide herd immunity
• What is herd immunity?


  When a large proportion of the population is vaccinated to prevent pathogen spread
• What are some ethical concerns involving vaccines?


  Potential harmful side effects and animal testing
• Describe the structure of HIV.


  Lipid envelope, attachment proteins, capsid, RNA, reverse transcriptase
• How does HIV replicate?


  HIV RNA is converted to DNA and integrated into T helper cells
• How can HIV be transmitted?


  Sexually, through needles, and open wounds
• How does HIV cause AIDS?


  By killing T helper cells, making the body susceptible to infections
• Why are antibiotics ineffective against AIDS?


  Antibiotics target bacterial cell walls, which viruses lack