Immune System
Level 1: Recognition Test
Time Limit: 20 minutes Total Marks: 30
Section A — Multiple Choice (1 mark each) [10 marks]
Choose the single best answer.
Q1. Which of the following is a feature of innate immunity?
- A) It is highly specific to a particular pathogen
- B) It provides immediate, non-specific defence
- C) It generates immunological memory
- D) It relies on antibody production
Q2. The skin acts primarily as a:
- A) Chemical barrier only
- B) Physical barrier
- C) Component of adaptive immunity
- D) Type of antibody
Q3. Which cell type carries out phagocytosis?
- A) B lymphocyte
- B) Macrophage
- C) Plasma cell
- D) Mast cell
Q4. During the inflammatory response, histamine causes:
- A) Vasoconstriction and reduced blood flow
- B) Vasodilation and increased capillary permeability
- C) Antibody synthesis
- D) Clonal deletion of T cells
Q5. Antibodies are produced by:
- A) Plasma cells (derived from B cells)
- B) Cytotoxic T cells
- C) Neutrophils
- D) Macrophages
Q6. The region of an antibody that binds to a specific antigen is the:
- A) Constant region
- B) Heavy chain hinge
- C) Variable region
- D) Disulphide bridge
Q7. MHC molecules function to:
- A) Digest pathogens in lysosomes
- B) Present antigen fragments on the cell surface
- C) Release histamine
- D) Form the mucus layer
Q8. Injection of pre-formed antibodies (e.g. antivenom) is an example of:
- A) Active natural immunity
- B) Active artificial immunity
- C) Passive artificial immunity
- D) Innate immunity
Q9. A secondary immune response is characterised by:
- A) Slower and weaker antibody production
- B) Faster, stronger antibody production due to memory cells
- C) No antibody production
- D) Only innate mechanisms
Q10. An autoimmune disorder occurs when the immune system:
- A) Fails to respond to any pathogen
- B) Attacks the body's own (self) cells
- C) Overreacts to a harmless allergen
- D) Cannot produce phagocytes
Section B — Matching (1 mark each) [8 marks]
Match each term in Column X to its correct description in Column Y. Write the letter.
| Column X | Column Y |
|---|---|
| Q11. Cytotoxic T cell | A. Engulfs and digests pathogens by phagocytosis |
| Q12. B cell | B. Kills infected body cells directly |
| Q13. Neutrophil | C. Differentiates into antibody-secreting plasma cells |
| Q14. Helper T cell | D. Activates B cells and other T cells via cytokines |
| Q15. Lysozyme | E. Enzyme in tears/saliva that breaks bacterial cell walls |
| Q16. Memory cell | F. Provides rapid response on re-exposure to antigen |
| Q17. Mast cell | G. Releases histamine to trigger inflammation |
| Q18. Antibody | H. Protein that binds specific antigen, tagging it for destruction |
Section C — True/False with Justification (2 marks each) [12 marks]
State whether TRUE or FALSE (1 mark) and give a brief justification (1 mark).
Q19. Vaccination produces active artificial immunity.
Q20. Passive immunity provides long-lasting protection because it generates memory cells.
Q21. Herd immunity protects unvaccinated individuals when a high proportion of a population is immune.
Q22. Humoral immunity is mediated mainly by antibodies in blood and lymph, whereas cell-mediated immunity involves T cells acting on infected cells.
Q23. An allergy is an underactive immune response to a dangerous pathogen.
Q24. Phagocytes are part of the adaptive immune system because they are specific to one pathogen.
Answer keyMark scheme & solutions
Section A — MCQ (1 mark each)
Q1. B — Innate immunity is immediate and non-specific; specificity and memory (A, C, D) belong to adaptive immunity. (1)
Q2. B — Skin is the primary physical barrier preventing pathogen entry. (1)
Q3. B — Macrophages (and neutrophils) are professional phagocytes; B cells and plasma cells make antibodies. (1)
Q4. B — Histamine causes vasodilation and increased capillary permeability, producing redness, heat, and swelling. (1)
Q5. A — Activated B cells differentiate into plasma cells that secrete antibodies. (1)
Q6. C — The variable region (antigen-binding site) determines specificity; the constant region is identical within a class. (1)
Q7. B — MHC molecules display antigen fragments to T cells (antigen presentation). (1)
Q8. C — Pre-formed antibodies given artificially = passive artificial immunity (no memory produced). (1)
Q9. B — Memory cells enable a faster, stronger secondary response. (1)
Q10. B — Autoimmunity = failure of self-tolerance; immune system attacks self cells. (1)
Section B — Matching (1 mark each)
| Q | Answer | Reason |
|---|---|---|
| Q11 | B | Cytotoxic T cells kill infected cells directly |
| Q12 | C | B cells become plasma cells |
| Q13 | A | Neutrophils phagocytose pathogens |
| Q14 | D | Helper T cells coordinate via cytokines |
| Q15 | E | Lysozyme digests bacterial cell walls |
| Q16 | F | Memory cells give rapid re-exposure response |
| Q17 | G | Mast cells release histamine |
| Q18 | H | Antibodies bind antigen for destruction |
(Total 8 marks, 1 each)
Section C — True/False with Justification (2 marks each)
Q19. TRUE (1) — Vaccination introduces antigen; the body actively makes its own antibodies and memory cells → active artificial immunity. (1)
Q20. FALSE (1) — Passive immunity supplies ready-made antibodies; it is short-lived and produces no memory cells, so protection is temporary. (1)
Q21. TRUE (1) — When enough people are immune, pathogen transmission is interrupted, indirectly protecting the non-immune. (1)
Q22. TRUE (1) — Humoral = B-cell/antibody mediated in body fluids; cell-mediated = T cells targeting infected/abnormal cells. (1)
Q23. FALSE (1) — An allergy is an overactive (hypersensitive) response to a harmless allergen, not an underactive response to a pathogen. (1)
Q24. FALSE (1) — Phagocytes are non-specific and belong to the innate immune system; they engulf many pathogens without specificity. (1)
Mark Summary
- Section A: 10 marks
- Section B: 8 marks
- Section C: 12 marks
- Total: 30 marks
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{"claim":"Section B has 8 matching items at 1 mark = 8 marks","code":"result = (8*1 == 8)"},
{"claim":"Section C has 6 true/false items at 2 marks = 12 marks","code":"result = (6*2 == 12)"},
{"claim":"Total paper marks equal 30","code":"secA=10; secB=8; secC=6*2; result = (secA+secB+secC == 30)"},
{"claim":"Total number of questions is 24","code":"result = (10+8+6 == 24)"}
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