C3.2 Defence against disease (Organisms): Practice Questions

• a.Prothrombin
• b.Thrombin
• c.Fibrin
• d.Platelets

• a.They use antibiotics to destroy the pathogen before it can infect cells.
• b.They stimulate a primary immune response, leading to the production of memory cells.
• c.They coat the body's cells with a protective layer that prevents viral entry.
• d.They provide a high concentration of ready-made antibodies to neutralize the pathogen.

• a.

  Failure of central or peripheral tolerance mechanisms, allowing self-reactive lymphocytes to become active.

• b.

  Overproduction of immunoglobulins by plasma cells, leading to widespread inflammation.

• c.

  Increased phagocytic activity of macrophages, leading to excessive destruction of body cells.

• d.

  Lack of appropriate antigen presentation by MHC molecules, leading to an unresponsive immune system.

• a.They produce specific antibodies to neutralize toxins.
• b.They act as a physical barrier and trap pathogens with sticky secretions.
• c.They release clotting factors to seal wounds in the skin.
• d.They identify and destroy body cells that have been infected by viruses.

• a.Viruses lack their own metabolic pathways and instead rely on the host cell's machinery.
• b.Viral antigens change too rapidly for antibiotics to remain effective.
• c.The protein coat of a virus is impermeable to the chemical structure of antibiotics.
• d.Antibiotics are only able to target organisms that contain a nucleus.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.