CBSE · Class 12 · Biology · Chapter 8

Human Health
and Disease

Complete chapter resources for CBSE Class 12 Biology — topic breakdown, key concepts, immunity mechanisms, sample questions, previous year board questions, and instant AI question paper generation.

4Topics
5–7Board marks
8Sample questions
3PYQ included
Sign Up Free & Generate → See sample questions ↓

Free for independent teachers · No credit card required

Key Concepts — Chapter 8
  • Immunity types: Innate (non-specific) vs. Acquired (specific)
  • Acquired immunity: Active (self-generated) vs. Passive (transferred)
  • Antibody structure: 2 heavy (H) + 2 light (L) chains; Fab (variable) + Fc (constant)
  • HIV target: CD4+ T-helper lymphocytes → depleted in AIDS
  • Malaria vector: Female Anopheles mosquito; pathogen: Plasmodium
  • Cancer: Proto-oncogene → oncogene; benign vs. malignant tumour
Chapter Overview

What this chapter covers

Chapter 8 of NCERT Class 12 Biology begins by defining health as a state of complete physical, mental, and social well-being — not merely the absence of disease. The chapter classifies diseases into infectious (communicable) and non-infectious categories, and introduces common pathogens: bacteria (typhoid, pneumonia), viruses (common cold, influenza, HIV), parasites (malaria, ascariasis, amoebiasis), and fungi. Each disease is studied for its causative organism, mode of transmission, characteristic symptoms, and preventive strategies.

A substantial portion of the chapter is devoted to immunity. The NCERT text distinguishes innate immunity (barriers — physical, physiological, cellular, cytokine) from acquired immunity (antibody-mediated via B-lymphocytes and cell-mediated via T-lymphocytes). Key concepts include the structure of an immunoglobulin (IgG), the memory response of acquired immunity, active vs. passive immunisation, and the mechanism of vaccination. The concept of lymphoid organs — primary (thymus, bone marrow) and secondary (spleen, lymph nodes, tonsils, Peyer's patches) — is explicitly examined in board papers.

The chapter closes with AIDS (HIV life cycle, CD4+ T-cell depletion, ELISA diagnosis), cancer (oncogenes, carcinogens, metastasis, treatment modalities), and drug and alcohol abuse (opioids, cannabinoids, barbiturates; effects on the body and prevention). These three topics carry the highest probability of appearing as 3–5 mark questions in the CBSE board exam.

Topics

What's inside Chapter 8

As per NCERT Class 12 Biology (CBSE syllabus)

Topic 1
Common Diseases in Humans
Bacterial diseases (typhoid, pneumonia), viral diseases (common cold, HIV/AIDS), parasitic infections (malaria, ascariasis, amoebiasis) — causative agents, symptoms, transmission, and prevention.
Topic 2
Immunity
Innate vs. acquired immunity; types of barriers; antibody-mediated (humoral) and cell-mediated immunity; structure of IgG; active vs. passive immunity; vaccination and immunisation; lymphoid organs.
Topic 3
AIDS
HIV structure and life cycle; infection of CD4+ T-helper cells; progression to AIDS; modes of transmission; ELISA and Western blot diagnosis; preventive measures and antiretroviral therapy.
Topic 4
Cancer and Drug Abuse
Cancer: oncogenes, carcinogens, benign vs. malignant tumours, metastasis, treatment (surgery, radiation, chemotherapy). Drug/alcohol abuse: opioids, cannabinoids, barbiturates, effects on health and prevention.
Connections

How this chapter fits in

Useful for setting question difficulty and cross-chapter papers.

Builds on
Ch 6 · Molecular Basis of Inheritance
Gene expression, DNA replication — basis for HIV retrovirus mechanism
Ch 7 · Evolution
Pathogen adaptation and host-pathogen co-evolution concepts
Chapter 8 Human Health
& Disease
Leads to
Ch 9 · Strategies for Enhancement in Food Production
Disease-resistant crops and animal husbandry health aspects
Ch 11 · Biotechnology and Its Applications
Recombinant vaccines, therapeutic proteins, and diagnostics
Board Blueprint

Marks & question-type breakdown

Typical pattern based on CBSE Class 12 Biology board papers from the last five years.

Question type Marks Typical count What's usually tested
MCQ / Assertion-Reason 1 1–2 Type of immunity, HIV target cell, vaccine type, or cancer term definition
Very Short Answer 2 1 Name the pathogen/vector, distinguish innate vs. acquired, define a term
Short Answer 3 1 HIV life cycle, structure of antibody, types of lymphoid organs
Long Answer / Case-Based 5 0–1 Detailed immunity mechanism, cancer vs. normal cell biology, drug abuse effects
Total (approximate) 5–7 3–5 Weightage varies across paper sets and years
Sample Questions

8 sample questions — generated by MarksZen AI

Aligned to CBSE Class 12 Biology Chapter 8. Covers all question types across Easy, Medium, and Hard difficulty.

Q1 Easy 1 mark MCQ
Which of the following is the correct vector–disease pair? (a) Female Culex mosquito — Malaria (b) Female Anopheles mosquito — Malaria (c) Female Aedes mosquito — Typhoid (d) Male Anopheles mosquito — Dengue
Q2 Easy 2 marks Short Answer
Differentiate between active immunity and passive immunity. Give one example of each.
Q3 Medium 2 marks Short Answer
Name the primary and secondary lymphoid organs in humans. State the role of the thymus in immune function.
Q4 Medium 3 marks Short Answer
Draw a labelled diagram of an antibody (IgG) molecule. Name the two types of polypeptide chains and identify the antigen-binding site.
Q5 Medium 3 marks Short Answer
Describe the life cycle of Plasmodium vivax in the human body. At which stage does the patient experience chills and high fever?
Q6 Hard 4 marks Long Answer
Explain the mechanism by which HIV causes AIDS. Why do AIDS patients become susceptible to opportunistic infections? Mention two diagnostic tests used to confirm HIV infection.
Q7 Hard 5 marks Long Answer
What are oncogenes? Explain how a proto-oncogene becomes an oncogene. Distinguish between a benign and a malignant tumour. Name three treatment approaches for cancer and state the principle behind each.
Q8 Hard 5 marks Case-Based
Read the passage and answer the questions: A 17-year-old student was found repeatedly consuming a prescribed cough syrup containing codeine, reporting it made him feel relaxed and euphoric. Over months he showed mood swings, withdrawal from family, and declining academic performance. (i) To which class of drugs does codeine belong? (ii) Name two long-term physiological effects of opioid abuse. (iii) How does the drug produce a feeling of euphoria at the neurological level? (iv) Suggest two rehabilitation strategies.
Generate a full paper with answer key →

MarksZen AI creates a complete question paper with answer key in under 2 minutes.

Previous Year Questions

From CBSE board examinations

Actual questions from past Class 12 Biology board papers — Human Health and Disease chapter.

Board 20223 marks
Explain the mechanism of action of HIV after it enters the human body. How does it result in the deficiency of immune response in the infected person? (CBSE All India 2022)
Board 20232 marks
Differentiate between innate immunity and acquired immunity with reference to (i) specificity and (ii) memory. (CBSE Delhi 2023)
Board 20205 marks
(a) Draw a labelled diagram of an immunoglobulin molecule. (b) Describe antibody-mediated immunity and cell-mediated immunity, mentioning the type of lymphocyte involved in each. (c) Why is colostrum considered important for a new-born infant? (CBSE 2020)
For Teachers

Create a board-aligned
question paper in 2 minutes.

Pick chapter, set the question-type mix and total marks — MarksZen AI generates the full paper with answer key. CBSE, ICSE, and all State Boards supported.

  • All 4 topics of this chapter
  • MCQ + short answer + long answer
  • Answer key included
  • PDF export ready
Sign Up Free & Generate →
FAQ

Questions teachers ask

How many marks does Human Health and Disease carry in the CBSE Class 12 board exam? +
Human Health and Disease (Chapter 8) typically contributes 5–7 marks in the CBSE Class 12 Biology board exam. Questions appear as a 1-mark MCQ or assertion-reason, a 2–3 mark short answer on immunity or pathogens, and occasionally a 5-mark structured question. The chapter has featured in every board paper in recent years.
What is the difference between innate and acquired immunity for board exams? +
Innate (non-specific) immunity is present from birth and includes physical barriers (skin, mucus), physiological barriers (stomach acid, tears), phagocytes, and natural killer cells — it responds the same way every time. Acquired (adaptive/specific) immunity develops after exposure to an antigen; it has memory, specificity, and involves B-lymphocytes (antibody-mediated) and T-lymphocytes (cell-mediated). Board questions often ask students to distinguish them in a table or define active vs. passive acquired immunity.
Which diseases from this chapter appear most frequently in board papers? +
AIDS (HIV life cycle, modes of transmission, preventive measures), malaria (Plasmodium life cycle, role of Anopheles mosquito), typhoid (Widal test, Salmonella), cancer (benign vs. malignant, metastasis, carcinogens), and drug/alcohol abuse are the highest-frequency topics. Ascariasis and common cold appear as shorter questions. Expect at least one life-cycle diagram question on either malaria or Ascaris.
Is the structure of an antibody included in the CBSE Class 12 syllabus? +
Yes. The NCERT textbook includes the basic Y-shaped structure of an immunoglobulin with two heavy (H) chains and two light (L) chains linked by disulfide bonds, and the four regions: constant (Fc) and variable (Fab) regions. Board questions ask students to draw and label this structure or explain how it recognises antigens. IgG is the most commonly referenced class in NCERT examples.
How do I generate a custom question paper for Human Health and Disease using MarksZen? +
Sign up for a free MarksZen account, choose CBSE Class 12 Biology, select Chapter 8 (Human Health and Disease), set your preferred question-type mix (MCQ, short answer, case-based, long answer) and total marks — the AI generates a complete board-aligned paper with answer key in under 2 minutes, ready for PDF export.