CBSE Class 12 Biology Syllabus 2026-27
CBSE released the Class 12 Biology syllabus for the academic session 2026–27 on 1 April 2026. Students must follow this updated syllabus for board exam preparation.
This page explains the CBSE Class 12 Biology syllabus in a clear format. It covers unit-wise topics, chapter-wise syllabus, exam pattern, and marking scheme for the 2026–27 session. Students can use this information to identify important chapters and plan their study for the CBSE Board Exam 2027.
The syllabus follows the CBSE curriculum and NCERT guidelines. It includes theory topics, practical syllabus, and question pattern for the final board exam. CBSE may revise topics or weightage compared to the previous year, so learners should check the latest syllabus.
Download the official CBSE Class 12 Biology syllabus PDF (2026–27) to check all topics and exam pattern in one place.
CBSE Class 12 Biology Latest Syllabus 2026-27
Time: 03 Hours
Max. Marks: 70
| Units | 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 | ||
CBSE Class 12 Biology Syllabus 2026-27: Unit-wise Summary
Unit-VI Reproduction
Chapter-1: Sexual Reproduction in Flowering Plants
Flower structure; development of male and female gametophytes; pollination - types, agencies and examples; out breeding devices; pollen-pistil interaction; double fertilization; post fertilization events - development of endosperm and embryo, development of seed and formation of fruit; special modes- apomixis, parthenocarpy, polyembryony; Significance of seed dispersal and fruit formation.
Chapter-2: Human Reproduction
Male and female reproductive systems; microscopic anatomy of testis and ovary; gametogenesis -spermatogenesis and oogenesis; menstrual cycle; fertilisation, embryo development upto blastocyst formation, implantation; pregnancy and placenta formation (elementary idea); parturition (elementary idea); lactation (elementary idea).
Chapter-3: Reproductive Health
Need for reproductive health and prevention of Sexually Transmitted Diseases (STDs); birth control - need and methods, contraception and medical termination of pregnancy (MTP); amniocentesis; infertility and assisted reproductive technologies - IVF, ZIFT, GIFT (elementary idea for general awareness).
Unit-VII Genetics and Evolution
Chapter-4: Principles of Inheritance and Variation
Heredity and variation: Mendelian inheritance; deviations from Mendelism – incomplete dominance, co-dominance, multiple alleles and inheritance of blood groups, pleiotropy;
elementary idea of polygenic inheritance; chromosome theory of inheritance; chromosomes and genes; Sex determination - in humans, birds and honey bee; linkage and crossing over; sex linked inheritance - haemophilia, colour blindness; Mendelian disorders in humans - thalassemia; chromosomal disorders in humans; Down's syndrome, Turner's and Klinefelter's syndromes.
Chapter-5: Molecular Basis of Inheritance
Search for genetic material and DNA as genetic material; Structure of DNA and RNA; DNA packaging; DNA replication; Central Dogma; transcription, genetic code, translation; gene expression and regulation - lac operon; Genome, Human and rice genome projects; DNA fingerprinting.
Chapter-6: Evolution
Origin of life; biological evolution and evidences for biological evolution (paleontology, comparative anatomy, embryology and molecular evidences); Darwin's contribution, modern synthetic theory of evolution; mechanism of evolution - variation (mutation and recombination) and natural selection with examples, types of natural selection; Gene flow and genetic drift; Hardy - Weinberg's principle; adaptive radiation; human evolution.
Unit-VIII Biology and Human Welfare
Chapter-7: Human Health and Diseases
Pathogens; parasites causing human diseases (malaria, dengue, chikungunya, filariasis, ascariasis, typhoid, pneumonia, common cold, amoebiasis, ring worm) and their control; Basic concepts of immunology - vaccines; cancer, HIV and AIDS; Adolescence - drug and alcohol abuse.
Chapter-8: Microbes in Human Welfare
Microbes in food processing, industrial production, sewage treatment, energy generation and microbes as bio-control agents and bio-fertilizers. Antibiotics; production and judicious use.
Unit-IX Biotechnology and its Applications
Chapter-9: Biotechnology - Principles and Processes
Genetic Engineering (Recombinant DNA Technology).
Chapter-10: Biotechnology and its Applications
Application of biotechnology in health and agriculture: Human insulin and vaccine production, stem cell technology, gene therapy; genetically modified organisms - Bt crops; transgenic animals; biosafety issues, biopiracy and patents.
Unit-X Ecology and Environment
Chapter-11: Organisms and Populations
Population interactions - mutualism, competition, predation, parasitism; population attributes
- growth, birth rate and death rate, age distribution.
Chapter-12: Ecosystem
Ecosystems: Patterns, components; productivity and decomposition; energy flow; pyramids
of number, biomass, energy.
Chapter-13: Biodiversity and its Conservation
Biodiversity-Concept, patterns, importance; loss of biodiversity; biodiversity conservation;
hotspots, endangered organisms, extinction, Red Data Book, Sacred Groves, biosphere
reserves, national parks, wildlife, sanctuaries and Ramsar sites.
The following topics are included in the syllabus but will be assessed only formatively to
reinforce understanding without adding to summative assessments. The reduces academic stress while ensuring meaningful learning. Schools can integrate these with existing chapters as they align well. Relevant NCERT textual material is enclosed for reference.
Environmental Issues (available as a part of CBSE Reading Material):
Air pollution and its control, Water pollution and its control, Solid Wastes, Agro-chemicals and their effects, Radioactive wastes, Greenhouse effect and global warming, Ozone depletion in the stratosphere, Degradation by improper resource utilization and maintenance, deforestation.
Evaluation Scheme for Examination
Time: 03 Hours
Max. Marks: 30
| Evaluation Scheme | Marks |
| One Major Experiment 5 | 5 |
| One Minor Experiment 2 & 3 | 4 |
| Slide Preparation 1 & 4 | 5 |
| Spotting | 7 |
| Practical Record + Viva Voce (Credit to the students’ work over academic session may be given) | 4 |
| Investigatory Project and its Project Record + Viva Voce the | 5 |
| Total | 30 Marks |
A. List of Experiments
- Prepare a temporary mount to observe pollen germination.
- Study the plant population density by quadrat method.
- Study the plant population frequency by quadrat method.
- Prepare a temporary mount of onion root tip to study mitosis.
- Isolate DNA from available plant material such as spinach, green
pea seeds, papaya, banana etc.
B. Study and observe the following (Spotting):
- Flowers adapted to pollination by different agencies (wind, insects, birds).
- Pollen germination on stigma through a permanent slide or scanning electron micrograph.
- Identification of stages of gamete development, i.e., T.S. of testis and T.S. of ovary through permanent slides (from grasshopper/mice).
- Meiosis in onion bud cell or grasshopper testis through permanent slides.
- T.S. of blastula through permanent slides (Mammalian).
- Mendelian inheritance using seeds of different colour/sizes of any plant.
- Prepared pedigree charts of any one of the genetic traits such as rolling of tongue, blood groups, ear lobes, widow's peak and colour blindness.
- Controlled pollination - emasculation, tagging and bagging.
- Common disease causing organisms like Ascaris, Entamoeba, Plasmodium, any fungus causing ringworm through permanent slides, models or virtual images or specimens. Comment on symptoms of diseases that they cause.
- Models specimens showing symbiotic association in lichens, root nodules of leguminous plants, and parasitic mode of nutrition shown by Cuscuta on host.
- Flash cards / models showing examples of homologous and analogous organs.
Practical Examination for Visually Impaired Students of Classes XI and XII
Time: 02 Hours
Max. Marks: 30
| Topic | MARKS |
| Identification/Familiarity with the apparatus | 5 |
| Written test (Based on given / prescribed practicals) | 10 |
| Practical Records | 5 |
| Viva | 10 |
| Total | 30 |
General Guidelines
- The practical examination will be of two-hour duration. A separate list of ten experiments is included here.
- The written examination in practicals for these students will be conducted at the time of practical examination of all other students.
- The written test will be of 30 minutes duration.
- The question paper given to the students should be legibly typed. It should contain a total of 15 practical skill based very short answer type questions. A student would be required to answer any 10 questions.
- A writer may be allowed to such students as per CBSE examination rules.
- All questions included in the question paper should be related to the listed practicals. Every question should require about two minutes to be answered.
- These students are also required to maintain a practical file. A student is expected to record at least five of the listed experiments as per the specific instructions for each subject. These practicals should be duly checked and signed by the internal examiner.
- The format of writing any experiment in the practical file should include aim, apparatus required, simple theory, procedure, related practical skills, precautions etc.
- Questions may be generated jointly by the external/internal examiners and used for assessment.
- The viva questions may include questions based on basic theory / principle / concept, apparatus / materials / chemicals required, procedure, precautions, sources of error etc.
Class XII
A. Items for Identification/ familiarity with the apparatus for assessment in practicals (All experiments) Beaker, flask, petriplates, soil from different sites - sandy, clayey, loamy, small potted plants, aluminium foil, paint brush, test tubes, starch solution, iodine, ice cubes, Bunsen burner/spirit lamp/water bath, large flowers, Maize inflorescence, model of developmental stages highlighting morula and blastula of frog, beads/seeds of different shapes/size/texture Ascaris, Cactus/Opuntia (model).
B. List of Practicals
- Study of flowers adapted to pollination by different agencies (wind, insects).
- Identification of T.S of morula or blastula of frog (Model).
- Study of Mendelian inheritance pattern using beads/seeds of different
sizes/texture. - Preparation of pedigree charts of genetic traits such as rolling of tongue,
colour blindness. - Study of emasculation, tagging and bagging by trying out an exercise on
controlled pollination. - Identify common disease causing organisms like Ascaris (model) and learn some common symptoms of the disease that they cause.
- Comment upon the morphological adaptations of plants found in xerophytic
conditions.
Note: The above practicals may be carried out in an experiential manner rather than recording observations.
Prescribed Books:
- Biology, Class-XII, Published by NCERT.
- Other related books and manuals brought out by NCERT (includes
multimedia). - Biology Supplementary Material (Revised). Available on CBSE website.
- Reading Material Biology Class XII.
CBSE Class 12 Biology Question Paper Design 2026-27
| Competencies | |
| Demonstrate Knowledge and Understanding | 50% |
| Application of Knowledge / Concepts | 30% |
| Analyse, Evaluate and Create | 20% |
Note:
- Typology of questions: VSA including MCQs, Assertion – Reasoning type questions; SA; LA- I; LA-II; Source-based/ Case-based/ Passage-based/ Integrated assessment questions.
- An internal choice of approximately 33% would be provided.
Suggestive verbs for various competencies
- Demonstrate, Knowledge and Understanding
State, name, list, identify, define, suggest, describe, outline, summarize, etc. - Application of Knowledge/Concepts
Calculate, illustrate, show, adapt, explain, distinguish, etc. - Analyze, Evaluate and Create
Interpret, analyse, compare, contrast, examine, evaluate, discuss, construct, etc.
The Changes for Class 12 (2026-27) Year-end Board Examinations are as under:
| (Class-12) | ||
| Periodic Assessment | Academic Session 2025-26 | Academic Session 2026-27 |
| Composition of question paper for year-end examination/ Board Examination (Theory) |
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