• 1. 
    After an individual is exposed to a microbial infection, the immune system increases its activities. The graph summarises the timeline of the level of those activities. It is reasonable to conclude that

  • physical barriers include macrophages.
  • innate immunity lacks involvement of living cells.
  • lymph nodes are involved in the acquired immunity phase.
  • the protection developed against the disease ceases at the end of the infection.
  • 2. 
    In lymph nodes

  • white blood cells mature into T cells.
  • lymph drains back into the circulatory system.
  • old and damaged red blood cells are destroyed.
  • B and T cells gather and attach to foreign antigens.
  • 3. 
    White blood cells that are involved in the third line of defence of the immune system include

  • mast cells.
  • eosinophils.
  • lymphocytes.
  • macrophages.
  • 4. 
    The diagram shows a bacterial infection within a human. Cells moving from the blood vessel towards the bacteria

  • are natural killer cells.
  • would act as phagocytes.
  • cause vasodilation in the blood vessel.
  • release histamine in response to tissue damage.
  • 5. 
    An inflammation reaction involves the

  • release of histamines.
  • agglutination of bacteria.
  • production of immunoglobulin.
  • vaseconstriction of blood vessels.
  • 6. 
    Cytotoxic T cells are

  • antibodies.
  • able to kill virus-infected cells.
  • part of the humoral immune response.
  • part of the second line of the immune defence.
  • 7. 
    The part of the virus labelled R is its

  • antigenic marker.
  • lipid envelope.
  • protein coat.
  • viral genome.
  • 8. 
    One of the similarities between the defence mechanisms of a plant and an animal include the

  • production of memory cells.
  • release of immune cells through a circulatory system.
  • use of an epidermal layer to inhibit the invasion of pathogens.
  • production of salicylic acid to warn cells of an invading pathogen.
  • 9. 
    Cellular agents capable of causing infection of body cells include

  • prions.
  • toxins.
  • DNA viruses.
  • Gram-negative bacteria.
  • 10. 
    First-line defence mechanisms in humans include

  • development of fever.
  • the action of phagocytes.
  • the use of antibiotics.
  • the presence of cilia on some cells.
  • 11. 
    A typical characteristic of such a virus is that it

  • is destroyed by antibiotics.
  • releases toxins into the body of the host.
  • evades detection by the host's immune system.
  • manipulates the host cell's DNA to produce copies of itself.
  • 12. 
    The graph shows the antibody levels in the blood after a person has been exposed twice to the same pathogen. With regard to this pathogen we can conclude that

  • the person has a deficient immune response.
  • the virulence of the pathogen increased between the first and second exposures.
  • antibodies are only produced after a second exposure to the pathogen.
  • memory cells for antibodies against the pathogen exist at the time of the second exposure.
  • 13. 
    The lymphatic system

  • controls blood clotting.
  • contains red blood cells.
  • has vessels with thick, muscular walls.
  • contains phagocytic cells.
  • 14. 
    A young woman stood on a dirty, rusty nail. The diagrams show bacteria isolated from the wound and a range of antibodies that were already present in her body. The microorganism most likely to cause a severe infection is

  • M.
  • N.
  • O.
  • P.
  • 15. 
    First-line defences that mammals have against invasion by disease-causing bacteria include

  • lysozymes.
  • interferons.
  • antibodies.
  • cytotoxic T cell.
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