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NEET Biology
Class 12 Chapter 7

Frequently Asked Questions

Innate immunity is the body's natural, non-specific defense present from birth, whereas acquired immunity develops after exposure to specific antigens and provides immunological memory.

HIV attacks CD4+ helper T-lymphocytes, gradually weakening the immune system and increasing susceptibility to opportunistic infections.

Vaccines stimulate the immune system to produce antibodies and memory cells, providing long-term protection against specific infectious diseases.

Cancer may develop due to genetic mutations, carcinogenic chemicals, radiations, oncogenic viruses, and lifestyle-related risk factors that lead to uncontrolled cell division.

Human Health and Disease is a high-scoring NEET chapter that frequently includes NCERT-based conceptual, diagram-based, disease-related, and immunity-focused questions on HIV/AIDS, cancer, vaccination, and the human immune system.

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Class 12 Chapter 7: Human Health and Disease

Human Health and Disease focuses on understanding how the human body maintains health, fights infections, and responds to various diseases. The chapter explains pathogens, immunity, infectious and non-infectious diseases, allergies, autoimmune disorders, AIDS, cancer, and the harmful effects of drug and alcohol abuse. It also highlights preventive healthcare measures and the role of the immune system in protecting the body. Since many questions are directly based on NCERT facts, flowcharts, and diagrams, this chapter is one of the highest-weightage units in NEET Biology.

At ALLEN, these revision notes simplify Human Health and Disease through concise explanations, NCERT-based facts, labelled diagrams, important medical terms, and exam-oriented revision points. These notes are designed to help students build conceptual clarity and prepare effectively for NEET and CBSE Board examinations.

1.0Chapter Snapshot

Particular

Details

Chapter Name

Human Health and Disease

Class

12

Subject

Biology

Board

CBSE

Exam Relevance

NEET & CBSE Board

Chapter Type

Human Physiology & Immunology

Difficulty Level

Moderate

Revision Time

3–4 Hours

2.0Related Supporting Study Resources

Resource

Status

NCERT Solutions

Available Soon

Important Questions

Available Soon

NCERT-Based MCQs

Available Soon

Previous Years' Questions (PYQs)

Available Soon

Assertion & Reason Questions

Available Soon

Practice Worksheets

Available Soon

Quick Revision Notes PDF

Available Soon

Important Diagrams PDF

Available Soon

3.0Learning Outcomes

After completing this chapter, you will be able to:

  • Understand the concepts of health and disease.
  • Differentiate between innate and acquired immunity.
  • Explain infectious diseases and their causative organisms.
  • Describe immune disorders, allergies, and autoimmune diseases.
  • Understand the causes, transmission, and prevention of AIDS.
  • Explain the development and treatment of cancer.
  • Recognize the harmful effects of drug and alcohol abuse.
  • Solve NCERT and NEET-based conceptual questions confidently.

4.05-Minute Quick Revision

Must-Revise Concepts

  • Health and Disease
  • Pathogens
  • Innate Immunity
  • Acquired Immunity
  • Active & Passive Immunity
  • Vaccination and Immunization
  • Allergies
  • Autoimmune Disorders
  • AIDS (HIV)
  • Cancer
  • Drug and Alcohol Abuse
  • Adolescence and Substance Abuse

Important NCERT Facts

  • Innate immunity is the first line of defense against pathogens.
  • Acquired immunity is antigen-specific and has immunological memory.
  • HIV primarily infects helper T-lymphocytes (CD4+ T cells).
  • Cancer results from the uncontrolled division of abnormal cells.
  • ELISA is commonly used as a screening test for HIV infection.
  • Vaccination stimulates the body to develop active immunity.

Diagram Recall

  • Types of Immunity
  • Structure of HIV
  • Life Cycle of HIV
  • Immune Response
  • Cancer Cells
  • Modes of Drug Abuse

Quick Revision Tips

  • Memorize all types of immunity with examples.
  • Learn important diseases along with their causative organisms.
  • Revise HIV transmission, prevention, and diagnosis carefully.
  • Study cancer-causing agents and treatment methods.
  • Read every NCERT diagram, table, and highlighted point thoroughly.

5.0High Weightage Topics

Topic

NEET Importance

Difficulty Level

Innate & Acquired Immunity

Very High

Moderate

Active & Passive Immunity

High

Easy–Moderate

AIDS (HIV)

Very High

Moderate

Cancer

Very High

Moderate

Allergies & Autoimmune Disorders

High

Moderate

Vaccination & Immunization

High

Easy

Drug & Alcohol Abuse

High

Easy–Moderate

6.0NCERT Fact Box

Concept

Important Fact

First Line of Defence

Skin, mucus, and physiological barriers are part of innate immunity.

Acquired Immunity

Characterized by specificity and immunological memory.

HIV Target Cells

HIV mainly infects CD4+ helper T-lymphocytes.

HIV Test

ELISA is commonly used for screening, while confirmatory tests are performed later.

Cancer-causing Agents

Chemicals, radiations, viruses, and genetic mutations can induce cancer.

Vaccination

Vaccines stimulate the immune system to produce antibodies and memory cells.

Important NCERT Diagrams

HIV Structure, Immune Response, Types of Immunity

7.0Common Mistakes & NEET Tips

Common Mistake

Correct Approach

Confusing innate and acquired immunity

Innate immunity is present from birth, whereas acquired immunity develops after exposure to antigens.

Mixing active and passive immunity

Active immunity develops naturally or through vaccination, while passive immunity involves ready-made antibodies.

Incorrect HIV transmission methods

Learn the actual modes of transmission and avoid common misconceptions.

Confusing HIV with AIDS

HIV is the virus, whereas AIDS is the disease caused by prolonged HIV infection.

Ignoring NCERT disease examples

Memorize diseases, pathogens, and preventive measures from NCERT.

Forgetting immune cells

Revise the functions of B-lymphocytes, T-lymphocytes, macrophages, and antibodies.

Skipping NCERT diagrams

Diagram-based questions are common in NEET Biology.

8.0ALLEN Faculty Tips

  • Read every NCERT line carefully, especially the sections on immunity and AIDS.
  • Memorize important pathogens, diseases, and diagnostic tests.
  • Prepare comparison tables for innate vs acquired immunity and active vs passive immunity.
  • Revise cancer types, carcinogens, and treatment methods regularly.
  • Learn the causes and prevention of drug and alcohol abuse.
  • Solve Previous Years' Questions (PYQs) and NCERT-based MCQs to improve concept clarity.

9.0PYQ Trend Analysis

Human Health and Disease is one of the highest-weightage chapters in NEET Biology. Questions are frequently asked from immunity, HIV/AIDS, cancer, vaccination, allergies, and drug abuse.

Note: The trend below is based on the analysis of previous years' NEET question papers. The exact number of questions may vary each year.

Topic

Questions Asked (Last 5 Years)

Average Difficulty

Innate & Acquired Immunity

1–2

Moderate

Vaccination & Immunization

1

Easy

HIV/AIDS

1–2

Moderate

Cancer

1

Moderate

Allergies & Autoimmune Disorders

1

Moderate

Drug & Alcohol Abuse

1

Easy–Moderate

10.0Most Common Question Types

  • Comparing innate and acquired immunity.
  • Identifying types of immune responses.
  • Explaining HIV transmission, diagnosis, and prevention.
  • Solving questions on vaccines and immunization.
  • Identifying causes and characteristics of cancer.
  • Explaining allergies and autoimmune disorders.
  • Solving NCERT-based assertion-reason and diagram-based questions.
  • Answering Previous Years' NEET conceptual questions.

11.0Smart Revision Strategy

  1. Revise the concepts of health, disease, and immunity.
  2. Learn the differences between innate, acquired, active, and passive immunity.
  3. Memorize HIV structure, transmission, diagnosis, and prevention.
  4. Revise cancer causes, carcinogens, and treatment methods.
  5. Study vaccination, allergies, and autoimmune disorders.
  6. Practice all NCERT diagrams and biological terminology.
  7. Solve Previous Years' Questions (PYQs) and NCERT-based MCQs.
  8. Complete revision with a chapter-wise NEET mock test.

Table of Contents


  • 1.0Chapter Snapshot
  • 2.0Related Supporting Study Resources
  • 3.0Learning Outcomes
  • 4.05-Minute Quick Revision
  • 4.1Must-Revise Concepts
  • 4.2Important NCERT Facts
  • 4.3Diagram Recall
  • 4.4Quick Revision Tips
  • 5.0High Weightage Topics
  • 6.0NCERT Fact Box
  • 7.0Common Mistakes & NEET Tips
  • 8.0ALLEN Faculty Tips
  • 9.0PYQ Trend Analysis
  • 10.0Most Common Question Types
  • 11.0Smart Revision Strategy