Chapter 8: Human Health and Disease

CBSE Class 12 Biology PYQ Analysis (2021–2025)

Chapter Overview & Weightage

Most Important & Repeated Questions (2021–2025)

  • Repeated 5–6 times: Differentiate between innate and acquired immunity. Give examples. (3 marks)
  • Repeated 4–5 times: Explain the structure and life cycle of HIV. How does it cause AIDS? (5 marks)
  • Repeated 4 times: What is vaccination? Explain its principle with examples (e.g., smallpox, polio). (3–5 marks)
  • Repeated 3–4 times: Describe the causes and prevention of cancer. (3 marks)
  • Repeated 3 times: What are drugs and alcohol abuse? Explain their effects on health & society. (5 marks)
  • Repeated 3 times: Explain types of immune responses (active vs passive, humoral vs cell-mediated). (3 marks)
  • Repeated 2–3 times: What is allergy? Explain auto-immune disorders with examples. (3 marks)
  • Assertion-Reason (2023–2025): Assertion: AIDS is a syndrome, not a disease. Reason: It weakens the immune system leading to secondary infections. (Both true, reason explains – repeated 2x)

Important Keywords & Concepts to Memorize

  • Health, disease, pathogen, immunity, innate immunity (physical barriers, physiological barriers, cellular, cytokine), acquired immunity (active/passive), antigen, antibody, vaccination, immunization, immune system (lymphoid organs), AIDS (HIV), cancer (carcinogens, oncogenes, metastasis), drugs (opioids, cannabinoids, coca alkaloids), alcohol abuse, addiction, withdrawal, immune disorders (allergy, auto-immune like rheumatoid arthritis), primary/secondary lymphoid organs, B-lymphocytes, T-lymphocytes, macrophages, interferons, ELISA, recombinant vaccines.

Exam Strategy for Chapter 8 (2026 Boards)

This is Chapter 8 complete PYQ analysis.
If you want Chapter 9 or any other chapter, just say the chapter number or name.