Tamil Nadu Board of Secondary Education Class 12 Biology (Botany and Zoology) Syllabus - Free PDF Download
Tamil Nadu Board of Secondary Education Syllabus 2025-26 Class 12: The Tamil Nadu Board of Secondary Education Class 12 Biology (Botany and Zoology) Syllabus for the examination year 2025-26 has been released by the Tamil Nadu Board, Tamil Nadu Board of Secondary Education. The board will hold the final examination at the end of the year following the annual assessment scheme, which has led to the release of the syllabus. The 2025-26 Tamil Nadu Board of Secondary Education Class 12 Biology (Botany and Zoology) Board Exam will entirely be based on the most recent syllabus. Therefore, students must thoroughly understand the new Tamil Nadu Board of Secondary Education syllabus to prepare for their annual exam properly.
The detailed Tamil Nadu Board of Secondary Education Class 12 Biology (Botany and Zoology) Syllabus for 2025-26 is below.
Academic year:
Tamil Nadu Board of Secondary Education Class 12 Biology (Botany and Zoology) Revised Syllabus
Tamil Nadu Board of Secondary Education Class 12 Biology (Botany and Zoology) Course Structure 2025-26 With Marking Scheme
| # | Unit/Topic | Weightage |
|---|---|---|
| 1.01 | Asexual and Sexual Reproduction in Plants | |
| 1.02 | Classical Genetics | |
| 1.03 | Chromosomal Basis of Inheritance | |
| 1.04 | Principles and Processes of Biotechnology | |
| 1.05 | Plant Tissue Culture | |
| 1.06 | Principles of Ecology | |
| 1.07 | Ecosystem | |
| 1.08 | Environmental Issues | |
| 1.09 | Plant Breeding | |
| 1.1 | Economically Useful Plants and Entrepreneurial Botany | |
| 2.01 | Reproduction in Organisms | |
| 2.02 | Human Reproduction | |
| 2.03 | Reproductive Health | |
| 2.04 | Principles of Inheritance and Variation | |
| 2.05 | Molecular Genetics | |
| 2.06 | Evolution | |
| 2.07 | Human Health and Diseases | |
| 2.08 | Microbes in Human Welfare | |
| 2.09 | Applications of Biotechnology | |
| 2.1 | Organisms and Populations | |
| 2.11 | Biodiversity and Its Conservation | |
| 2.12 | Environmental Issues | |
| Total | - |
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Syllabus
1.01 Asexual and Sexual Reproduction in Plants
- Pre-fertilization in Plant: Structure and Events
- Post Fertilisation in Plant: Structures and Events
1.02 Classical Genetics
- Terminology Related to Mendelism
- Mendel’s analytical and empirical approach
- Extensions of Mendelian Genetics (Deviation from Mendelism)
- Intragenic Gene Interactions
- Lethal Genes
- Intergenic Gene Interactions
- Extra Chromosomal Inheritance or Extra Nuclear Inheritance (Cytoplasmic Inheritance)
1.03 Chromosomal Basis of Inheritance
- Biomolecules in the Cell > Proteins
- Linkage
- Coupling and Repulsion theory
- Kinds of Linkage
- Linkage Groups
- Linkage
- Extensions of Mendelian Genetics (Deviation from Mendelism)
1.04 Principles and Processes of Biotechnology
- Development of Biotechnology
- Method of Biotechnology
- Fermentation
- Single Cell Protein (SCP)
- Advancements in Modern Biotechnology
- Genetic Engineering
- Steps involved in Recombinant DNA Technology
- Tools for Genetic Engineering
- Restriction Enzymes
- DNA Ligase
- Alkaline Phosphatase
- Vectors
- Competent Host (For Transformation with Recombinant DNA)
- Methods of Gene Transfer
- Direct or Vectorless Gene Transfer
- Indirect or Vector-Mediated Gene Transfer
- Screening for Recombinants
- Insertional Inactivation - Blue-White Colony Selection Method
- Antibiotic resistant markers
- Replica plating technique
- Molecular Techniques - Isolation of Genetic Material and Gel Electrophoresis
- Nucleic Acid Hybridization - Blotting Techniques
- Bioassay for Target Gene Effect
- Genome Sequencing and Plant Genome Projects
- Evolutionary pattern assessed using DNA
- Genome editing and CRISPR - Cas9
- RNA Interference (RNAi)
- Transgenic Plants / Genetically Modified Crops (Gm Crops)
- Herbicide Tolerant – Glyphosate
- Herbicide Tolerant - Basta
- Insect resistance - Bt Crops
- Virus Resistance
- FlavrSavr Tomato
- Golden rice - Biofortification
- Polyhydroxybutyrate (PHB)
- Polylactic acid (PLA)
- Green Fluorescent Protein (GFP)
- Biopharming
- Bioremediation
- Biofuel: Algal Biofuel
- Bioprospecting
- Crop Biotechnology > Hybrid Seeds
- Definition: Hybrid Seeds
1.05 Plant Tissue Culture
- Plant Tissue Culture (PTC)
- Laboratory Facilities for PTC
- Technique Involved in PTC
- Types of Plant tissue cultures
- Plant Regeneration Pathway
- Somatic Embryogenesis
- Organogenesis
- Conservation of Plant Genetic Resources
- Germplasm Conservation
- Cryopreservation (–195.C)
- Intellectual Property Right (IPR)
- Patents
- Biosafety and Bioethics
- Future of Biotechnology
1.06 Principles of Ecology
- Ecological Factors
- Climatic Factors
- Edaphic factors
- Topographic factors
- Biotic factors
- Ecological Adaptations
- Dispersal of Fruits and Seeds
- Dispersal by Wind (Anemochory)
- Dispersal by Water (Hydrochory)
- Dispersal by Animals (Zoochory)
- Dispersal by Explosive Mechanism (Autochory)
1.07 Ecosystem
- Plant Succession
- Causes of Succession
- Characteristics of ecological succession
- Types of succession
- Process of succession
- Classification of plant succession
- Significance of Plant Succession
1.08 Environmental Issues
- Greenhouse Effect and Global Warming
- Key Points: Greenhouse Effect and Global Warming
- Forestry
- Agro forestry
- Social forestry
- Major activities of forestry extension centres
- Afforestation
- Alien Invasive Species
- Conservation
- International Union for Conservation of Nature (IUCN)
- Endemic Centres and Endemic Plants
- Carbon Capture and Storage (CCS)
- Rain Water Harvesting – RWH (Solution to Water Crisis – a Ecological Problem)
- Environmental benefits of Rain Water Harvesting
- Importance of Lakes
- Environmental Impact Assessment (EIA)
- Biodiversity Impact Assessment (BIA)
- Geographic Information System (GIS)
1.09 Plant Breeding
- Relationship Between Humans and Plants
- Domestication of Plants
- History of Agriculture
- Organic Agriculture
- Biofertilizers
- Plant Breeding
- Conventional Plant Breeding Methods
- Plant Introduction
- Selection
- Hybridization
- Heterosis
- Mutation Breeding
- Polyploid Breeding
- Green Revolution
- Plant Breeding for Developing Resistance to diseases
- Plant Breeding for Developing Resistance to Insect Pests
- Modern Plant Breeding
- New Plant Engineering Techniques / New Breeding Techniques (NBT)
1.1 Economically Useful Plants and Entrepreneurial Botany
- Food Plants
- Cereals
- Major Cereals
- Millets (Siru Thaniyangal)
- Minor Millets
- Pulses
- Vegetables
- Fruits
- Nuts
- Sugars
- Oil Seeds
- Beverages
- Spices and Condiments
- Spices
- Condiment
- Fibres
- Timber
- Seasoning of wood
- Grain, Texture, and Figure of wood
- Latex
- Pulp Wood
- Dye
- Dye and its Types
- Uses and Adverse Effects of Dyes
- Cosmetics
- Perfumes
- Traditional Systems of Medicines
- Siddha system of medicine
- Ayurveda system of medicine
- Medicinal Plants
- Entrepreneurial Botany
- Mushroom cultivation
- Single Cell Protein (SCP) Production
- Seaweed Liquid Fertilizer
- Organic farming
- Terrarium
- Cultivation of Medicinal and Aromatic Plants
2.01 Reproduction in Organisms
2.02 Human Reproduction
- Maintenance of Pregnancy and Embryonic Development
2.03 Reproductive Health
- Social Impact of Sex Ratio, Female Foeticide and Infanticide
- Population Explosion in India
- Definition
- Effects of Population Explosion
- Measures to Control Population Explosion
- Real-Life Application
- Key Point Summary
- Detection of Foetal Disorders During Early Pregnancy
- Ultrasound scanning
- Amniocentesis
- Chorionic villus sampling (CVS)
- Foetoscope
2.04 Principles of Inheritance and Variation
- Extensions of Mendelian Genetics (Deviation from Mendelism)
- Blood Transfusion and Blood Groups (ABO and Rh system)
- Definition: Blood Transfusion
- Definition: Blood Donor
- Definition: Blood Recipient
- Definition: Antigens
- Definition: Antibodies
- Definition: Universal Donor
- Definition: Universal Recipient
- Blood Groups
- Rh Factor
- Key Point: Blood Transfusion and Blood Groups
- Genetic Control of Rh Factor
- Fisher and Race hypothesis
- Wiener Hypothesis
- Incompatibility of Rh Factor – Erythroblastosis foetalis
- Prevention of Erythroblastosis foetalis
- Karyotyping
- Preparation of Karyotype
- Applications of Karyotyping
- Human Karyotype
2.05 Molecular Genetics
- Gene as the Functional Unit of Inheritance
- Chemistry of Nucleic Acids
- Pentose sugar
- Nitrogenous bases
- The phosphate functional group
- Nucleoside and nucleotide
2.06 Evolution
- Theories of Origin of Life
- Evidence of Evolution > Morphological Evidences
- Key Points: Morphological Evidences
- Theories of Biological Evolution
- Definition: Natural Selection
- Definition: Survival of the Fittest
- Organic Evolution
2.07 Human Health and Diseases
- Common Diseases in Human Beings
- Maintenance of Personal and Public Hygiene
- Basic Concepts of Immunology
- Innate immunity
- Acquired immunity
- Components of acquired immunity
- Types of acquired immunity
- Immune responses
- Primary immune response
- Secondary immune response
- Lymphoid organs
- Primary lymphoid organs
- Secondary or peripheral lymphoid organs
- Cells of the immune system
- Antigens
- Types of antigens
- Antibodies
- Antigen -antibody interaction
- Binding force of antigen - antibody reaction
- Different types of antigen and antibody reactions
- Vaccines
- Vaccination and immunization
- Hypersensitivity
- Autoimmune Diseases
- Tumour immunology
- Immunotherapy of cancer
- Mental Health – Depression
- Signs and symptoms of mental depression
2.08 Microbes in Human Welfare
- Bioremediation
- Microorganisms involved in bioremediation
2.09 Applications of Biotechnology
- Biological Products and Their Uses
2.1 Organisms and Populations
- Concept of Biome and Their Distribution
- Characters of a biome
- Aquatic Biomes
- Terrestrial biomes
- Major Biomes of the Earth
- Tundra Biome
- Taiga Biome
- Grassland Biome
- Alpine biome
- Forest biomes
- Desert biomes
- Organisms and Their Environment
- Responses to Abiotic Factors
- Responses to Abiotic Factors
- Living organisms deal with the extreme weather conditions through the following adaptations:
(i) Regulation
(ii) Conformation
(iii) Migration
(iv) Suspension
- Responses to Abiotic Factors
- Adaptations and Its Types
2.11 Biodiversity and Its Conservation
- Biogeographical Regions of India
- Threats to Biodiversity
- Causes of Biodiversity Loss
- Habitat Loss
- Habitat fragmentation
- Over exploitation
- Exotic species invasion
- Global Climate changes
- Shifting or Jhum cultivation (Slash-and-burn agriculture)
- Coextinctions
- Intensive agriculture
- Loss of biodiversity
- Hotspots
- Endangered organisms
- Extinction
- IUCN
- Red Data Book
2.12 Environmental Issues
- Biomagnification
- Types of Farming in India > Organic Farming
- Key Points: Organic farming
