The CBSE Class 12 Biology syllabus 2026-27 has five theory units and 13 chapters for the 2027 board exam. Biology carries 100 marks: 70 marks for the three-hour theory paper and 30 marks for the practical examination. The subject code is 044.

Genetics and Evolution carries 20 marks, the highest weightage among the five units. Environmental Issues remains part of classroom learning but is assessed only formatively, so it does not add marks to the final theory paper.

CBSE Class 12 Biology Syllabus 2026-27

The theory course starts with reproduction and inheritance, then moves to health, biotechnology and ecology. The five units are Reproduction, Genetics and Evolution, Biology and Human Welfare, Biotechnology and its Applications, and Ecology and Environment.

CBSE Class 12 Biology Syllabus 2026-27 PDF

The complete curriculum contains the theory topics, practical experiments, marks distribution, prescribed books and question paper design. Students can download the official Class 12 Biology syllabus PDF.

CBSE Class 12 Biology Unit-Wise Marks 2026-27

The 70 theory marks are divided among five units. Genetics and Evolution carries 20 marks, followed by Reproduction with 16 marks. Biology and Human Welfare and Biotechnology and its Applications carry 12 marks each, while Ecology and Environment carries 10 marks.

CBSE Class 12 Biology Chapter-Wise Syllabus 2026-27

Unit VI: Reproduction

Sexual Reproduction in Flowering Plants covers flower structure, gametophytes, pollination, fertilisation, seed and fruit formation, apomixis, parthenocarpy and polyembryony.

Human Reproduction includes the male and female reproductive systems, gametogenesis, the menstrual cycle, fertilisation, implantation, pregnancy, parturition and lactation.

Reproductive Health covers sexually transmitted diseases, contraception, medical termination of pregnancy, amniocentesis, infertility and assisted reproductive technologies such as IVF, ZIFT and GIFT.

Unit VII: Genetics and Evolution

Principles of Inheritance and Variation includes Mendelian inheritance, incomplete dominance, co-dominance, blood groups, linkage, sex-linked inheritance and chromosomal disorders.

Molecular Basis of Inheritance covers DNA and RNA, replication, transcription, translation, the genetic code, gene regulation, genome projects and DNA fingerprinting.

Evolution includes the origin of life, evidence for evolution, natural selection, mutation, gene flow, genetic drift, the Hardy-Weinberg principle, adaptive radiation and human evolution.

Unit VIII: Biology and Human Welfare

Human Health and Diseases covers pathogens, common human diseases, immunity, vaccines, cancer, HIV and AIDS, and drug and alcohol abuse during adolescence.

Microbes in Human Welfare explains the use of microbes in food processing, industrial production, sewage treatment, energy generation, biocontrol and biofertilisers. It also includes antibiotics and their careful use.

Unit IX: Biotechnology and its Applications

Biotechnology - Principles and Processes covers genetic engineering and recombinant DNA technology.

Biotechnology and its Applications includes human insulin, vaccine production, stem cells, gene therapy, Bt crops, transgenic animals, biosafety, biopiracy and patents.

Unit X: Ecology and Environment

Organisms and Populations covers population growth, birth and death rates, age distribution, mutualism, competition, predation and parasitism.

Ecosystem includes ecosystem components, productivity, decomposition, energy flow and ecological pyramids.

Biodiversity and its Conservation covers biodiversity patterns, biodiversity loss, hotspots, endangered organisms, extinction, the Red Data Book, sacred groves, biosphere reserves, national parks, wildlife sanctuaries and Ramsar sites.

CBSE Class 12 Biology Formative Topics 2026-27

Environmental Issues is included for classroom learning but is assessed only formatively. It does not add to the 70-mark summative theory paper.

CBSE Class 12 Biology Practical Syllabus 2026-27

The Biology practical examination carries 30 marks and lasts three hours. It includes one major experiment, one minor experiment, slide preparation, spotting, practical records, viva and an investigatory project.

Biology Practical Experiments and Spotting

The five listed experiments cover pollen germination, plant population density, plant population frequency, mitosis in an onion root tip and DNA isolation from plant material. Spotting includes pollination, reproductive tissues, meiosis, blastula, Mendelian inheritance, pedigree charts, controlled pollination, disease-causing organisms, symbiotic associations and homologous or analogous organs.

Practical Exam for Visually Impaired Students

The practical examination for visually impaired students lasts two hours. It gives 5 marks for identifying apparatus or material, 10 marks for a written test, 5 marks for practical records and 10 marks for viva.

CBSE Class 12 Biology Question Paper Design 2026-27

Half of the theory paper checks knowledge and understanding. Application-based questions make up 30%, while analysis, evaluation and creation make up the remaining 20%.

The paper may include MCQs, assertion-reasoning questions, short and long answers, and source-, case- or passage-based questions. Internal choice is available in about 33% of the paper. The broader Class 12 exam pattern explains the common board paper structure.

CBSE Class 12 Biology Prescribed Books

The prescribed book is NCERT Biology for Class 12. CBSE also includes related NCERT books and manuals, revised Biology supplementary material and the Class 12 Biology reading material. The Class 12 books page contains the current textbook details.

The Class 12 subject-wise syllabus and 2026 question papers cover the other board-exam subjects and practice material.