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A Level Biology: Immunity MCQs — Biology

24 multiple-choice questions on A Level Biology: Immunity from Biology, each with the correct answer and, where available, a teacher's explanation. Read through them to revise the chapter, then practise the same questions one by one to test yourself.

1. An antigen is

  1. a protein made by plasma cells
  2. a type of phagocyte
  3. a hydrolytic enzyme
  4. a molecule that stimulates an immune response

Answer: D) a molecule that stimulates an immune response

Explanation: Antigens trigger antibody production. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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2. The hinge region of an antibody

  1. contains haem
  2. binds phagocytes
  3. gives flexibility for binding two antigens
  4. is the variable region

Answer: C) gives flexibility for binding two antigens

Explanation: Flexibility aids binding. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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3. Plasma cells

  1. kill infected cells
  2. engulf pathogens
  3. secrete antibodies
  4. present antigens

Answer: C) secrete antibodies

Explanation: Plasma cells are antibody factories. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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4. Which cells release cytokines that activate B-lymphocytes?

  1. Red blood cells
  2. T-helper cells
  3. Neutrophils
  4. T-killer cells

Answer: B) T-helper cells

Explanation: T-helper cells coordinate the response. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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5. The variable region of an antibody

  1. binds to phagocytes
  2. is the same in all antibodies
  3. is a disulfide bond
  4. forms the antigen-binding site

Answer: D) forms the antigen-binding site

Explanation: Variable regions are specific. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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6. Vaccination gives

  1. artificial passive immunity
  2. natural active immunity
  3. natural passive immunity
  4. artificial active immunity

Answer: D) artificial active immunity

Explanation: The body makes its own antibodies after a vaccine. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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7. Smallpox could be eradicated partly because

  1. the virus had stable antigens and no animal reservoir
  2. it had many antigen types
  3. antibiotics killed it
  4. it was a bacterium

Answer: A) the virus had stable antigens and no animal reservoir

Explanation: One vaccine worked worldwide. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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8. In phagocytosis, hydrolytic enzymes come from

  1. mitochondria
  2. ribosomes
  3. lysosomes
  4. the nucleus

Answer: C) lysosomes

Explanation: Lysosomes fuse with phagosomes. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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9. Clonal selection is when

  1. lymphocytes with receptors complementary to an antigen are activated
  2. all lymphocytes divide
  3. phagocytes engulf pathogens
  4. antibodies clump bacteria

Answer: A) lymphocytes with receptors complementary to an antigen are activated

Explanation: Only matching lymphocytes are selected. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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10. Plasma cells contain a lot of rough ER because they

  1. store lipids
  2. photosynthesise
  3. digest pathogens
  4. synthesise large amounts of protein (antibodies)

Answer: D) synthesise large amounts of protein (antibodies)

Explanation: Antibodies are proteins made on RER. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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11. A baby receiving antibodies in breast milk has

  1. natural passive immunity
  2. artificial active immunity
  3. natural active immunity
  4. artificial passive immunity

Answer: A) natural passive immunity

Explanation: Antibodies from mother, naturally. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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12. Why is it hard to vaccinate against influenza?

  1. The virus frequently changes its antigens
  2. It lives only in animals
  3. It has no antigens
  4. It is a bacterium

Answer: A) The virus frequently changes its antigens

Explanation: Antigenic variation. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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13. Antibodies are made of

  1. carbohydrate only
  2. one polypeptide
  3. three chains in a triple helix
  4. two heavy and two light polypeptide chains

Answer: D) two heavy and two light polypeptide chains

Explanation: Four chains joined by disulfide bonds. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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14. Monoclonal antibodies are used in pregnancy tests to detect

  1. oestrogen
  2. insulin
  3. glucose
  4. hCG

Answer: D) hCG

Explanation: hCG is made by the embryo. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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15. B-lymphocytes mature in the

  1. bone marrow
  2. spleen only
  3. liver
  4. thymus

Answer: A) bone marrow

Explanation: T-cells mature in the thymus. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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16. Passive immunity does not last long because

  1. it uses vaccines
  2. no memory cells are formed
  3. it destroys lymphocytes
  4. antibodies are too large

Answer: B) no memory cells are formed

Explanation: Antibodies are broken down. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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17. Self antigens are

  1. molecules on the body's own cells that do not normally trigger a response
  2. only found on bacteria
  3. antibodies
  4. foreign proteins

Answer: A) molecules on the body's own cells that do not normally trigger a response

Explanation: Self vs non-self recognition. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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18. Injection of anti-venom gives

  1. herd immunity
  2. artificial passive immunity
  3. natural active immunity
  4. artificial active immunity

Answer: B) artificial passive immunity

Explanation: Ready-made antibodies are injected. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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19. Agglutination is

  1. the bursting of bacteria
  2. the engulfing of pathogens
  3. the clumping of pathogens by antibodies
  4. the release of cytokines

Answer: C) the clumping of pathogens by antibodies

Explanation: Antibodies have two binding sites. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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20. The secondary immune response is faster than the primary response because

  1. more macrophages are present
  2. pathogens are weaker
  3. antibodies are injected
  4. memory cells are already present

Answer: D) memory cells are already present

Explanation: Memory cells divide rapidly. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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21. In the hybridoma method, B-lymphocytes are fused with

  1. red blood cells
  2. myeloma (cancer) cells
  3. macrophages
  4. T-killer cells

Answer: B) myeloma (cancer) cells

Explanation: Cancer cells divide indefinitely. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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22. T-killer cells

  1. secrete antibodies
  2. digest bacteria in phagosomes
  3. destroy infected body cells
  4. become plasma cells

Answer: C) destroy infected body cells

Explanation: Cell-mediated killing. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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23. Herd immunity occurs when

  1. everyone has had the disease
  2. pathogens mutate
  3. antibodies are given to all
  4. enough people are vaccinated that the pathogen cannot spread

Answer: D) enough people are vaccinated that the pathogen cannot spread

Explanation: Few susceptible hosts remain. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

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24. Macrophages act as antigen-presenting cells by

  1. displaying the pathogen's antigens on their surface
  2. storing memory
  3. killing infected cells
  4. making antibodies

Answer: A) displaying the pathogen's antigens on their surface

Explanation: They present antigens to lymphocytes. AS & A Level Biology · Topic 11 Immunity · 11.1 The immune system

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