Tamil Nadu Class 12 Biology Syllabus 2025 is divided into two main subjects. Students will be taking separate exams for Zoology and Botany under the Biology subjects in the Tamil Nadu 12th Board 2025 examination. The TN 12th Biology syllabus 2025 is divided into zoology and botany, containing various topics under each subject. Units allotted for Botany are Taxonomy of angiosperms, Plant anatomy, Cell biology and genetics, Biotechnology, Plant physiology, and Biology in human welfare. Chapters allotted for Zoology are Human Physiology, Microbiology, Immunology, Genetics, Environmental Sciences, Biology Applications, and Evolution Theories. The TN 12th biology paper has four sections and is conducted for 150 marks. Make sure to complete the Tamil Nadu 12th Syllabus 2025 on time and prepare for the board exams accordingly.
The revised TN 12th Biology syllabus 2025 was made available online in PDF format by the Directorate of Government Examinations, Tamil Nadu. It includes the marking scheme, important topics, marks distribution, and necessary instructions to follow while appearing for the TN 12th board exams. Check more information about the Tamil Nadu Class 12 Biology Syllabus 2025 here:
DownloadTamil Nadu Class 12th Biology-Botany Syllabus 2025-26 here
DownloadTamil Nadu Class 12th Biology-Zoology Syllabus 2025-26 here
Tamil Nadu Class 12 Biology Syllabus 2025
Students must prepare separately for Botany and Zoology. They can check out the details related to the syllabus for both the subjects from the tables given below:
Botany
Refer to the table given below to learn more about the chapters that will be included in botany and the topics allotted for each chapter:
Unit | Topics |
Taxonomy of angiosperms | Type of classification such as artificial, natural, phylogenetic, biosystematics, binomial nomenclature herbarium and their uses classification of plant families such as Malvaceae, Solanaceae, Euphorbiaceae, Liliaceae, and their economic importance |
Plant anatomy | Tissue and tissue system anatomy of monocot and dicot root Anatomy of monocot and dicot stem Anatomy of dicot leaf |
Cell biology and genetics | Chromosome structure and types Genes and genomes linkage and crossing over gene mapping recombination of chromosomes mutation and Chromosome aberrations DNA as a genetic material its structure and replication of DNA Structure of RNA and its type |
Biotechnology | Recombinant DNA technology, transgenic plants and microbes, plant tissue culture and its application, protoplast fusion, SCP |
Plant physiology | Photosynthesis its significance and photochemical reactions, electron transport system, photorespiration Factors affecting photosynthesis mode of nutrition Chemosynthesis respiration, glycolysis, Krebs cycle aerobic respiration and anaerobic respiration Fermentation Plant growth regulators phytohormones such as auxins, gibberellins, cytokinin, ethylene, ABA. photoperiodism and vernalization |
Biology in human welfare | Food production Important varieties Role of biofertilizers Crop diseases and their control Biopesticides Genetically modified organisms Bio war Biopiracy Biopatent Sustainable agriculture medicinal plants including microbes economic importance of crops. |
Zoology
Students can check out the details related to the chapters included in the Zoology subject from the table given below:
Unit | Topics |
Human physiology | Nutrition- carbohydrates, proteins, lipids, balanced diet, malnutrition, digestive enzymes, illness to human bodies Bones and joints- muscles Respiration-breathing, Circulation-including heart functioning, myocardial infarction, atherosclerosis, ECG, heart valves, blood pressure, heart transplantationPlasma- corpuscles, anticoagulants Coordinating system- including brain functioning, memory, diseases, spinal cord functioning, reflex action Chemical coordination- thyroid, parathyroid, insulin, hormones of the adrenal cortex and medulla, reproductive hormones Receptor organs -including eyes, ears, skin, tongue excretion kidney Reproductive system- spermatogenesis and oogenesis menstrual cycle, in vitro fertilization, birth control, STD, and AIDS. |
Microbiology | Introduction Influence of Louis Pasteur, koch Virology genetics AIDS and its control bacteriology, protozoan microbiology, and larval microbiology Pathogenicity of microorganisms. |
Immunology | Immune system- Innate immunity- lymphoid cells, mononuclear phagocytes, cytokines, structure of antibody, antigen-antibody reaction Acquired immunity- development of the immune system, T-cell activation, monoclonal body, cytotoxicity, infections and immunity, immunity and tissue transplantation, immune-related disease. |
Genetics | Human genome project, genetic disease, karyotyping Recombinant DNA technology, cloning, transgenic organisms, genetically modified organisms, gene therapy, bioinformatics, DNA sequencing, protein sequencing, protein structure, database. |
Environmental Sciences | Human population, global warming, ozone layer depletion, waste management, biodiversity conservation, energy crisis, environmental impact, Poverty. |
Biology applications | Livestock and Management, milch breed, draught breed, common diseases and control, poultry farming, pisciculture, urine analysis, CT scan, artificial pacemaker. |
Evolution theories | Lamarkism, Darwinism, the modern concept of natural selection, species concept, the origin of species, and isolating mechanisms. |
Tamil Nadu Class 12 Biology Marking Scheme 2025
The TN 12th Biology exam is conducted for 150 marks, and students must complete the paper within 3 hours. The biology exam paper consists of short, long, and objective questions. The marking scheme for the TN 12th biology exam is given below.
Sections | Type of Question | Total Questions | Marks |
A | Objective | 30 | 30 |
B | Very short | 20 | 45 |
C | Short | 12 | 35 |
D | Long | 8 | 40 |
Total | 150 |
Tamil Nadu Class 12th Biology syllabus 2025-26: How to Download
Tamil Board 12th syllabus shall be downloaded by following the steps shown below.
Step 1: First and foremost one has to visit the official website of the Tamil Board.
Step 2: After that go to the primary menu on the home page and click on the option of the syllabus.
Step 3: A new window will pop up which will show the syllabus for all the individual streams and the subjects will also be mentioned there in PDF format.
Step 4: The candidates need to click onto the link to the PDF so as to download the syllabus.
