ISC Class 12 Biology Syllabus 2026 | Free PDF Download

ISC Class 12 Biology syllabus has been released officially. The ISC biology syllabus class 12 focuses on conceptual clarity and practical application, making it important for competitive exams like NEET. Let’s break down the complete Biology Syllabus Class 12 ISC and everything you need to know about it!

Also, don’t forget to check out the ISC Class 12 Chemistry Syllabus to streamline your science preparation.

ISC Class 12 Biology Syllabus PDF – Download the Latest PDF

The syllabus for 2025-26 is now available. It’s essential for students, parents, and teachers to review these updates. Click the link below to download the Biology Syllabus Class 12 ISC PDF and begin your preparations!

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Assessment Structure for Class 12 Biology Syllabus

Your ISC Biology syllabus Class 12 assessment is divided into two sections—external and internal examinations. Here's how your marks are distributed:

• Theory (External Exam): 70 Marks
• Practical (Internal Assessment): 30 Marks

The external exam will test your conceptual knowledge, while the internal assessment includes practicals and project work.

Marking Scheme - Before jumping into the Biology Syllabus Class 12 ISC, let’s understand how your exam will be marked:

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ISC Biology Syllabus Class 12 Detailed Breakdown

The syllabus is designed to strengthen your core understanding of biological sciences. Here’s what you’ll be studying:

1. Reproduction

(i) Sexual Reproduction in Flowering Plants

• Flower Structure: Complete anatomy with diagrams
• Gametophyte Development: Male and female development processes
• Microsporogenesis: Structure of microsporangium, T.S. of anther, pollen development
• Megasporogenesis: Structure of megasporangium, female gametophyte development
• Pollination: Types (autogamy, chasmogamy, cleistogamy, geitonogamy, xenogamy)
• Pollination Adaptations: Wind, water, and insect pollination adaptations
• Self-Pollination Prevention: Mechanisms and outbreeding devices
• Pollen-Pistil Interaction: Compatibility/incompatibility mechanisms
• Fertilization: Double fertilization, triple fusion, post-fertilization events
• Artificial Hybridization: Procedure (emasculation and bagging) and significance
• Seed & Fruit Development: Endosperm types (cellular, nuclear, helobial), embryo formation
• Special Modes: Apomixis, parthenocarpy, polyembryony
• Seed Types: Albuminous and non-albuminous seeds, monocot and dicot seed structure
• Fruits: Classification, structure of typical fruits (mango, coconut)
• Seed Dispersal: Significance and mechanisms

(ii) Human Reproduction

• Reproductive Systems: Male and female anatomy and microscopic structure
• Gametogenesis: Spermatogenesis and oogenesis processes
• Hormonal Control: Of gametogenesis and reproductive cycles
• Menstrual Cycle: Phases, hormone action, comparison with estrous cycle
• Fertilization: Physico-chemical events during fertilization
• Embryonic Development: Implantation, blastocyst formation, key developmental stages
• Pregnancy: Placenta formation and functions
• Parturition and Lactation: Hormonal control and significance

(iii) Reproductive Health

• Family Planning: Need and methods, population control
• Contraception: Natural methods (periodic abstinence, withdrawal, lactational amenorrhea)
• Artificial Contraception: Barriers, IUDs, oral pills, spermicides, implants, surgical methods
• Medical Termination of Pregnancy (MTP): Definition and reasons
• Amniocentesis: Role in detecting genetic defects
• Assisted Reproductive Technologies: IVF, IUT, ZIFT, ICSI, GIFT, AI, IUI
• Sexually Transmitted Diseases: Causes, symptoms, prevention of various STDs

2. Genetics and Evolution

(i) Principles of Inheritance and Variation

• Mendelian Inheritance: Principles, reasons for Mendel's success
• Basic Terminology: Homologous chromosomes, autosomes, sex chromosomes, alleles
• Genetic Crosses: Monohybrid, dihybrid, test cross, back cross with Punnett squares
• Deviations from Mendelism: Incomplete dominance, co-dominance, multiple alleles
• ABO Blood Groups: Pattern of inheritance
• Polygenic Inheritance: Example of skin color in humans
• Pedigree Analysis: Creation and interpretation of pedigree charts
• Pleiotropy: With examples of PKU and starch synthesis
• Chromosomal Theory: Of inheritance
• Sex Determination: In humans, birds, honey bees, grasshoppers
• Sex-Linked Inheritance: Examples in Drosophila and humans
• Linkage and Crossing Over: Definition and significance
• Mutation: Types - spontaneous, induced, gene (point, frameshift)
• Human Genetic Disorders: Phenylketonuria, thalassemia, color blindness, sickle cell anemia
• Chromosomal Disorders: Down's, Klinefelter's, Turner's syndromes

(ii) Molecular Basis of Inheritance

• Genetic Material: Properties and discovery experiments (Griffith, Hershey-Chase, Avery et al.)
• DNA Structure: Double helix model, contributions of various scientists
• DNA vs RNA: Differences and types of RNA (tRNA, mRNA, rRNA, snRNA, hnRNA)
• Central Dogma: Including reverse transcription
• DNA Replication: Mechanism, enzymes involved, experimental evidence
• Transcription: Process and post-transcriptional modifications
• Genetic Code: Discovery and essential features
• Translation: Protein synthesis, particularly in prokaryotes
• Gene Expression: Lac operon in E. coli as an example
• Human Genome Project: Goals, methodologies, features, applications
• DNA Fingerprinting: Technique, applications, ethical issues

(iii) Evolution

• Origin of Life: Theories including abiogenesis, biogenesis, panspermia, spontaneous generation
• Modern Concept: Oparin-Haldane theory, Miller-Urey experiment
• Evidences of Evolution: Morphological, embryological, paleontological, biogeographical, molecular
• Homologous vs Analogous Organs: Definitions and examples
• Vestigial Organs: Concept and significance
• Theory of Recapitulation: Ontogeny vs phylogeny
• Fossils: Definition and radioactive carbon-dating
• Geological Time Scale: With reference to dominant flora and fauna
• Darwinism: Key features, Malthus's contribution, examples of natural selection
• Neo-Darwinism: Modern Synthetic Theory components
• Population Genetics: Gene flow, genetic drift, mutation, recombination
• Hardy-Weinberg Principle: Equilibrium and factors affecting it (with numerical problems)
• Variations: Causes and types of natural selection
• Human Evolution: Features of ancestral species from Dryopithecus to Homo sapiens sapiens

3. Biology and Human Welfare

(i) Human Health and Diseases

• Communicable Diseases: Modes, causative agents, symptoms, prevention
• Viral Diseases: Common cold, chikungunya, dengue
• Bacterial Diseases: Typhoid, pneumonia, diphtheria, plague
• Protozoal Diseases: Amoebiasis, malaria (life cycle of Plasmodium)
• Helminthic Diseases: Ascariasis, filariasis
• Fungal Diseases: Ringworms
• Cancer: Types, causes, diagnosis, treatment, characteristics of cancer cells
• Allergies: Definition and general symptoms
• Immunity Types: Innate (physical, physiological, cellular, cytokine barriers)
• Acquired Immunity: Active, passive, humoral, cell-mediated
• Interferons: Definition, source, function
• Antibodies: Structure and types (IgG, IgA, IgM, IgD, IgE)
• Vaccination & Immunization: Principles
• Autoimmunity: Concept
• Lymphoid Organs: Primary and secondary
• AIDS: Causative agent, transmission, diagnosis, symptoms, retrovirus replication, prevention
• Substance Abuse: Effects of alcoholism and smoking
• Drugs: Effects of opioids, cannabinoids, cocaine, barbiturates
• Addiction: Reasons, prevention, control

(ii) Microbes in Human Welfare

• Household Products: Lactobacillus (curd), Saccharomyces (bread), Propionibacterium (cheese)
• Industrial Products: Beverages, antibiotics (Penicillin discovery and use)
• Organic Acids & Enzymes: Microbial sources and industrial applications
• Pharmaceuticals: Sources and applications of Cyclosporin-A, Statins
• Sewage Treatment: Primary and secondary treatment processes
• Biogas Production: Methanogens, biogas plant design, composition, production process
• Biocontrol Agents: Various biological pest control methods
• Biofertilizers: Types (Rhizobium, Azospirillum, etc.) and applications
• IPM: Integrated Pest Management
• Chemical Pesticides: Harmful effects

4. Biotechnology and Its Applications

(i) Biotechnology - Principles and Processes

• Genetic Engineering: Definition and principles
• DNA Isolation: Methods from various cell types
• Gene Isolation: By electrophoresis
• Recombinant DNA Formation: Steps and process
• Restriction Enzymes: Discovery, nomenclature, features, roles (EcoRI, HindII)
• Cloning Vectors: Features of good vectors, examples (pBR322, etc.)
• Vector Transfer Methods: Direct methods, microinjection, gene gun
• Recombinant Selection: Antibiotic resistance, blue-white selection
• Gene Amplification: In vivo and in vitro (PCR) methods
• Bioreactors: Features and types (stirred tank, sparged tank)
• Downstream Processing: Concept and steps

(ii) Biotechnology and its Applications

• Agricultural Applications:
  
  1. Micropropagation and somatic hybridization
  2. GM crops resistant to abiotic stresses
  3. Pest-resistant crops (Bt-crops, RNAi)
  4. Nutritionally enhanced crops (golden rice)
• Medical Applications:
  
  1. Insulin and vaccine production
  2. Stem cell technology and applications
  3. Gene therapy (SCID treatment)
  4. Molecular diagnostics (PCR, ELISA, DNA/RNA probes)
• Transgenic Animals: For bioactive products, safety testing, disease studies
• Regulatory Bodies: Role of GEAC
• Biopiracy & Biopatents: Definitions, examples, ethical issues

5. Ecology and Environment

(i) Organisms and Populations

• Population Attributes: Sex ratio, age distribution pyramids
• Population Measurements: Density, natality, mortality, emigration, immigration, carrying capacity
• Population Growth: Factors, models (exponential and logistic) with equations and graphs
• Life History Variations: Reproductive fitness
• Population Interactions: Mutualism, competition, predation, parasitism, commensalism, amensalism
• Competition Types: Interspecific, interference, competitive release, Gause's Principle
• Predation: Adaptations to avoid predation
• Parasitism: Types (ecto-, endo-, brood parasites)

(ii) Ecosystem

• Ecosystem Types: Various classifications
• Structure: Biotic and abiotic components
• Pond Ecosystem: Structure and function
• Productivity: Gross primary productivity (GPP), net primary productivity (NPP), secondary productivity
• Decomposition: Processes and factors affecting rate
• Energy Flow: Various food chains and webs
• Trophic Levels: Organization and relationships
• Ecological Pyramids: Energy, number, biomass
• Key Concepts: PAR, 10% Law, standing crop, standing state

(iii) Biodiversity and its Conservation

• Biodiversity Types: Species, ecosystem, genetic with examples
• Global Biodiversity: Proportionate distribution across taxa
• Biodiversity Patterns: Latitudinal gradients, species-area relationship
• Rivet Popper Hypothesis: Concept and implications
• Importance of Species Diversity: Utilitarian and ethical perspectives
• Extinct Organisms: Recent examples and causes
• Biodiversity Loss: Habitat loss, fragmentation, over-exploitation, alien species, co-extinction
• Conservation Methods: In-situ: Protected areas, biosphere reserves, national parks, sanctuaries, sacred groves. Ex-situ: Captive breeding, zoos, botanical gardens, cryopreservation, wildlife safari, seed banks

6. ISC Biology Syllabus Class 12 PRACTICAL WORK (15 Marks)

(1) Taxonomy

Study of floral characteristics through dissection of flowers from 7 families:

1. Malvaceae (China rose/Hollyhock)
2. Leguminosae (Sweet pea/Pea/Bean, etc.)
3. Solanaceae (Petunia/Datura/Brinjal)
4. Liliaceae or Amaryllidaceae (various lilies)
5. Cruciferae (mustard, candytuft)
6. Compositae/Asteraceae (sunflower, chrysanthemum, etc.)
7. Gramineae/Poaceae (wheat, corn, rice)

Skills required: Flower dissection, vertical section cutting, floral diagram drawing with mother axis, formula writing, family identification

(2) Biochemical and Physiological Experiments

Stomata Study: Arrangement/distribution in dicot and monocot leaves

Soil Analysis: Comparative study of soil samples from different sites

1. Texture (loamy, sandy, clayey)
2. Moisture content
3. Humus content
4. Water holding capacity
5. pH

Enzyme Action: Effect of temperature and pH on starch solution

1. Testing at low (<10°C), optimum (37°C), and high (>70°C) temperatures
2. Testing in acidic, neutral, and basic conditions

DNA Isolation: From plant materials (spinach, green pea, banana, papaya)

(3) Slide Preparation

• Germination of pollen grain in nutrient medium
• T.S. of ovary showing placentation
• T.S. of hydrophyte stem
• T.S. of xerophytic leaf (Nerium)
• L.S. of monocot and dicot seeds

(4) Spotting (3 minutes per spot)

Identification and Features:

1. T.S. of mammalian ovary and testis
2. Germinating pollen grain
3. T.S. of ovary showing placentation types
4. T.S. of blastula/blastocyst
5. Whole mounts of Plasmodium and Entamoeba
6. Ascaris specimens

Ecological Adaptations: Plants and animals from xeric and aquatic habitats

Flower Adaptations: For insect, water, and wind pollination

7. PROJECT WORK AND PRACTICAL FILE (15 Marks)

a) Project Work (10 Marks)

• One handwritten original investigatory project on any biological topic
• Suggested topics in biology syllabus class 12 ISC include genetic disorders, gene therapy, Human Genome Project, DNA fingerprinting, biopiracy, cancer, AIDS, drug addiction, microorganisms in industry, human population, etc.

b) Evaluation Criteria in ISC Biology:

• Content
• Introduction
• Presentation (graphs, tables, charts, diagrams, etc.)
• Conclusion/Summary
• Bibliography

Preparation Tips for Biology Board Exam Class 12

Scoring high in ISC Biology Class 12 is all about strategy! Follow these tips to boost your performance:

1. Know your syllabus– Biology Syllabus Class 12 ISC cover all important topics. Use it for thorough understanding.
2. Practice Previous Year Questions (PYQs) – Solving PYQs helps you get familiar with question patterns. 
3. Use Sample Papers for Revision – Time yourself while solving sample papers to improve speed and accuracy.
4. Make Flashcards for Quick Revisions – Use them to memorize scientific names, definitions, and diagrams.
5. Focus on Diagrams & Labelling – Diagrams play a crucial role in scoring full marks in the theory paper.
6. Revise Smartly – Summarize each chapter in one page and use flowcharts to retain information easily.

The ISC Class 12 Biology syllabus is well-structured to enhance both theoretical knowledge and practical skills. With the right study plan and resources, you can ace the subject effortlessly. Stay consistent, practice regularly, and make the most of your study time. All the best!

Frequently Asked Questions

What is the structure of the ISC Class 12 Biology exam?

The exam is divided into two parts: Theory and Practical. The theory paper focuses on topics like Genetics, Physiology, Ecology, and Biotechnology, while the practical exam tests your skills in conducting experiments, observations, and data interpretation.

What are the key topics in the ISC Class 12 Biology syllabus?

Key topics include Reproduction, Genetics and Evolution, Human Physiology, Plant Physiology, Biotechnology and Its Applications, Ecology and Environment, and Human Health and Diseases. The syllabus also covers Molecular Biology and Biomolecules.

What types of questions are asked in the Biology exam?

The exam includes a mix of multiple-choice questions (MCQs), short-answer questions, and long-answer questions. You may be asked to explain concepts, diagrams (e.g., structure of cells or human organs), and write detailed answers for certain topics.

How can I prepare for the ISC Class 12 Biology exam?

Focus on understanding the concepts thoroughly. Revise important diagrams (like the structure of flowers, human organs, etc.), practice writing structured answers, and solve previous years’ papers for time management. For practicals, be sure to review common experiments and their procedures.

Is there a specific marking scheme for the Biology exam?

Yes, the marking scheme awards marks for both theoretical understanding and application. Long-answer questions generally carry more weight, and diagram-based questions often have marks for both labeling and explanation. MCQs are also important for quick revision of basic concepts.