Students who fail to obtain the minimum passing marks in the CBSE Class 12 Biology exam must appear for the compartment examination. This exam provides a second opportunity to save the academic year and continue with higher education. Since Biology is a core subject in the medical and life sciences field, understanding the compartment syllabus is crucial for focused and efficient preparation.
The Biology syllabus comprises topics grouped under five main units, including reproduction, genetics and evolution, human welfare, biotechnology, and ecology. The compartment exam follows the same syllabus as the annual board exam to ensure consistency in evaluation.
Chapter-Wise Weightage
The CBSE Class 12 Biology syllabus is divided into five units, each with specific mark allocations. The table below outlines the unit-wise distribution of marks:
| Unit | Title | Marks |
|---|---|---|
| VI | Reproduction | 16 |
| VII | Genetics and Evolution | 20 |
| VIII | Biology and Human Welfare | 12 |
| IX | Biotechnology and Its Applications | 12 |
| X | Ecology and Environment | 10 |
| Total | 70 |
Unit-Wise Chapters and Topics
Unit VI: Reproduction
Chapter 2: Sexual Reproduction in Flowering Plants
Flower structure, development of gametophytes, types of pollination, double fertilization, post-fertilization events, apomixis, parthenocarpy, polyembryony, and seed dispersal.
Chapter 3: Human Reproduction
Male and female reproductive systems, gametogenesis, menstrual cycle, fertilization, embryo development, implantation, placenta formation, parturition, and lactation.
Chapter 4: Reproductive Health
Importance of reproductive health, prevention of STDs, contraception, medical termination of pregnancy (MTP), infertility, and assisted reproductive technologies (ARTs) such as IVF, ZIFT, and GIFT.
Unit VII: Genetics and Evolution
Chapter 5: Principles of Inheritance and Variation
Mendelian inheritance, blood groups, pleiotropy, polygenic inheritance, sex determination, linkage and crossing over, chromosomal disorders (Down’s, Turner’s, Klinefelter’s).
Chapter 6: Molecular Basis of Inheritance
Structure and replication of DNA, transcription, translation, gene regulation (lac operon), genome projects (human and rice), and DNA fingerprinting.
Chapter 7: Evolution
Origin of life, Darwin's theory, natural selection, types of selection, Hardy-Weinberg principle, genetic drift, adaptive radiation, and human evolution.
Unit VIII: Biology and Human Welfare
Chapter 8: Human Health and Diseases
Human pathogens and diseases (malaria, dengue, typhoid, etc.), immunity and vaccination, HIV/AIDS, drug and alcohol abuse.
Chapter 10: Microbes in Human Welfare
Role of microbes in food production, industry, sewage treatment, biofertilizers, antibiotics, and biocontrol.
Unit IX: Biotechnology and Its Applications
Chapter 11: Biotechnology - Principles and Processes
Principles of genetic engineering and recombinant DNA technology.
Chapter 12: Biotechnology and Its Applications
Applications in agriculture and medicine, GMOs, gene therapy, stem cell technology, biosafety, and biopiracy.
Unit X: Ecology and Environment
Chapter 13: Organisms and Populations
Population interactions (mutualism, competition, predation), growth patterns, birth and death rates, age distribution.
(Note: Topics like abiotic factors and adaptations are excluded.)
Chapter 14: Ecosystem
Structure, components, energy flow, food chains, ecological pyramids.
(Note: Nutrient cycles and ecological succession are excluded.)
Chapter 15: Biodiversity and Its Conservation
Concept and importance of biodiversity, threats, conservation strategies, hotspots, biosphere reserves, national parks, sanctuaries, Ramsar sites.
Biology Practical Evaluation Scheme (Total: 30 Marks)
For General Students
| Component | Marks |
| One Major Experiment | 5 |
| One Minor Experiment | 4 |
| Slide Preparation | 5 |
| Spotting | 7 |
| Practical Record + Viva Voce | 4 |
| Investigatory Project + Viva Voce | 5 |
| Total | 30 |
For Visually Impaired Students
| Component | Marks |
| Identification/Familiarity with Apparatus | 5 |
| Written Test (Based on Practical Topics) | 10 |
| Practical Records | 5 |
| Viva | 10 |
| Total | 30 |
The CBSE Class 12 Biology Compartment Syllabus 2025 offers a clear roadmap for students aiming to pass the exam in their second attempt. With detailed unit-wise distribution and an established practical scheme, students can plan their preparation effectively. Staying focused on key concepts and consistent practice will greatly improve the chances of passing the compartment exam successfully.
