CBSE Class 12 Biology Syllabus 2025-26 - CBSE 12th Class Biology Syllabus Download PDF

CBSE Class 12 Biology Syllabus 2025-26: CBSE Class 12 Biology syllabus for 2025–26 includes five major theory units along with practical components. CBSE 12th Biology syllabus 2025-26 comprises a total of 5 units and 15 chapters. The practical exam is divided into 4 parts. The biology exam will be conducted for a total of 100 marks—70 marks for the theory paper and 30 marks for the practical assessment. Some of the key topics included in the syllabus are Reproduction, Genetics and Evolution, Biology and Human Welfare, and Ecology and Environment. CBSE has recommended the NCERT book for class 12 biology preparation. Along with the syllabus Central Board of Secondary Education has made available the CBSE Class 12 Exam Pattern 2025-26 . Students need to make sure that they complete as many CBSE 12th Biology sample papers and CBSE Class 12 Biology previous years' question papers as possible to self-evaluate their preparation after reviewing the entire syllabus and the CBSE Exam Pattern. Read the article to know more about the detailed CBSE Class 12 Biology Syllabus 2025. Check CBSE 12th Biology Syllabus 2025-26 for theory and practical exam, along with the marking scheme here.

CBSE Class 12 Biology Syllabus 2025-26

The CBSE Class 12 Biology syllabus for 2025–26 outlines all the important topics students need to study for both the theory and practical exams. It includes a clear breakdown of chapters across five main units. Students can download the syllabus in PDF format to easily check which chapters are covered, along with the list of experiments and spotting activities they’ll need to prepare for the practical exam.

Particulars	PDF Link
CBSE Class 12 Biology Syllabus 2025-26	Download PDF

CBSE Class 12 Biology 2025-26: Course Structure

The CBSE Class 12 Biology syllabus is helpful for students to understand which topics are most important and how marks are distributed. It can make exam preparation more focused and efficient, especially with board exams approaching. The syllabus is also a great resource for students planning to appear for competitive exams. Check the course content below:

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

CBSE Class 12 Biology Syllabus 2025-26

Class 12 Biology covers various important topics, such as cell structure and function, ecology, biotechnology, genetics, and human physiology. Check the detailed CBSE Class 12 Biology syllabus here.

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 8 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. (Topics excluded: Organism and its Environment, Major Aboitic Factors, Responses to Abioitic Factors, Adaptations) 9

Chapter 12: Ecosystem
Ecosystems: Patterns, components; productivity and decomposition; energy flow; pyramids of number, biomass, energy (Topics excluded: Ecological Succession and Nutrient Cycles).

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.

CBSE Class 12 Biology Marking Scheme 2025

The table below includes the marks for the CBSE Class 12 Biology theory exam. Students can find out the important chapters according to the marks allotted to them, and prepare accordingly for board exams.

Topics	Marks
Reproduction	16
Genetics and Evolution	20
Biology and Human Welfare	12
Biotechnology and its Applications	12
Ecology and Environment	10
Total Marks	70

CBSE conducts Class 12 Biology practical exam for 30 marks. The distribution of marks is presented in the table below:

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	4
Investigatory Project and its Project Record + VIVA Voce	5
Total Marks	30

List of Experiments

• Prepare a temporary mount to observe pollen germination.
• Study the plant population density by the quadrat method.
• Study the plant population frequency by the 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.
• 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.

CBSE 12th Practical Exam for Visually Impaired Students: Evaluation Scheme

Topic	Marks
Identification/Familiarity with the apparatus	5
Written test (Based on given/prescribed practicals)	10
Practical Records	5
Viva	10
Total	30

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 the 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.

CBSE Class 12 Biology Question Paper Pattern 2025-26

Biology paper carries 70 marks for theory and 30 marks for practical. Tabulated below is the updated CBSE class 12 exam pattern for Biology.

Question Paper Design (Theory) 2025
Competencies
Demonstrate the Knowledge and Understanding	50%
Application of Knowledge / Concepts	30%
Analyse, Evaluate and Create	20%

• Types of questions: Source-based, Case-based, Passage-based, Integrated assessment questions; SA; Assertion-Reasoning type questions; VSA with MCQs.
• There would be an internal choice of about thirty-three percent.

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.

CBSE Class 12 Biology Prescribed Books

Students of CBSE 12th science stream must follow the NCERT Books for Biology. Other than these, students can refer to other reference books as well for better preparation. Some of the CBSE Class 12 Biology prescribed books are:

• Biology, Class-XII, Published by NCERT
• Other related books and manuals brought out by NCERT (consider multimedia also)
• Biology Supplementary Material (Revised). Available on the CBSE website.

How to Download CBSE Class 12 Biology Syllabus 2025-26

Students can visit the official website of the CBSE Board to download the CBSE Class 12 Biology Syllabus 2025-26. To download the syllabus online, they can follow the steps given below:

• Step 1: Visit the official website of CBSE at cbseacademic.nic.in.
• Step 2: From the overview page, look for the ‘Curriculum’ tab.
• Step 3: Select the ‘Senior Secondary Curriculum (XI-XII)’ option.
• Step 4: Then select Academic Electives (Group A).
• Step 5: Select the Biology syllabus. The Biology curriculum for class 12 CBSE will appear on the screen. Save the syllabus as a PDF.

General Guidelines

In the practical examination, students will get a two-hour duration. The question paper will include 15 practical skill-based very short answer-type questions. Out of this, 10 questions will have to be answered by students. The questions should be based on the listed practicals. Students should aim to answer every question within two minutes.

In the practical file, students are expected to record at least five experiments. They must follow the correct format of writing an experiment in the practical file, which includes aim, apparatus required, simple theory, procedure, related practical skills, precautions, etc. These practicals will be checked and signed by the internal examiner. During the viva, questions may be generated based on basic theory/principle/concept, apparatus/materials/chemicals required, procedure, precautions, sources of error etc.