AHSEC HS 2nd Year Biology Syllabus 2025-26: The Higher Secondary Final Year Biology syllabus has been revised with updated unit-wise marks, chapter distribution and practical components. Students will study Botany and Zoology separately, with a total of 70 theory marks and 180 teaching periods. Below is the complete, easy-to-understand WordPress-ready syllabus.
AHSEC HS 2nd Year Biology Syllabus 2025–26
| Particular | Details |
|---|---|
| Subject Name | Biology |
| Class | HS 2nd Year (Class 12) |
| Board | Assam Higher Secondary Education Council (AHSEC) |
| Exam Duration | 3 Hours |
| Total Marks | 100 (Theory + Practical) |
| Academic Year | 2025–2026 |
| Official Website | ahsec.assam.gov.in |
AHSEC HS 2nd Year Biology Syllabus Overview
| Group | Units Covered | Marks | Periods |
|---|---|---|---|
| Botany | Units VI to X | 35 | 90 |
| Zoology | Units VI to X | 35 | 90 |
| Total | — | 70 Marks | 180 Periods |
GROUP–A: BOTANY SYLLABUS
Unit VI: Sexual Reproduction (Chapter 1)
Marks: 05 | Periods: 17
Topics Covered
- Flower as an organ of sexual reproduction
- Pre-fertilization: structures & events
- Double fertilization
- Post-fertilization changes
- Apomixis and polyembryony
Unit VII: Genetics & Evolution (Chapter 6)
Marks: 05 | Periods: 13
Topics Covered
- Mendelian genetics
- Inheritance patterns
- Chromosomal theory
- Linkage & recombination
- Sex determination
- Mutations
- Genetic disorders
Unit VIII: Biology in Human Welfare (Chapter 8)
Marks: 04 | Periods: 10
Topics Covered
- Microbes in household, industrial and sewage treatment
- Biogas production
- Biological control
- Biofertilizers
Unit IX: Biotechnology & Applications (Ch. 9 & 10)
Marks: 12 | Periods: 30
Topics Covered
- Principles of biotechnology
- Tools (restriction enzymes, vectors, plasmids)
- rDNA technology process
- Applications in agriculture & medicine
- Transgenic organisms
- Ethical issues
Unit X: Ecology (Ch. 12 & 14)
Marks: 09 | Periods: 20
Note: 3 compulsory marks from Chapter 14
Topics Covered
- Ecosystem structure & functions
- Productivity and decomposition
- Energy flow & ecological pyramids
- Bioresources of Assam:
- Medicinal plants: Sarpagandha, Neem, Tulsi, Cinchona, Atropa
- Timber plants: Teak, Sal, Sissoo, Gomari, Hollong
- Sericogenic resources: Muga, Eri
GROUP–B: ZOOLOGY SYLLABUS
Unit VI: Reproduction (Ch. 2 & 3)
Marks: 08 | Periods: 20
Topics Covered
- Human reproductive system
- Gametogenesis
- Menstrual cycle
- Fertilization, implantation, embryo development
- Reproductive health, STDs, birth control
- ART methods (IVF, ICSI, etc.)
Unit VII: Genetics & Evolution (Ch. 4 & 5)
Marks: 12 | Periods: 35
Topics Covered
- Mendel’s laws
- One-gene and two-gene inheritance
- Sex linked inheritance
- Mutations
- DNA structure, replication, transcription
- Translation, genetic code
- Gene regulation
- Human Genome Project
- DNA fingerprinting
- Evolution theories and mechanisms
Unit VIII: Biology in Human Welfare (Ch. 7)
Marks: 05 | Periods: 12
Topics Covered
- Diseases: Typhoid, Pneumonia, Malaria, Ascariasis, Ringworm, etc.
- Immunity
- AIDS
- Cancer
- Drug & alcohol abuse
Unit IX: Biotechnology (Ch. 10 — Transgenic Animals Only)
Marks: 01 | Periods: 01
Topics Covered
- Transgenic animals
- Applications
Unit X: Ecology (Ch. 11, 13 & 14)
Marks: 09 | Periods: 22
Note: 3 compulsory marks from Chapter 14
Topics Covered
- Organisms & populations
- Population interactions
- Biodiversity & conservation
- National parks & sanctuaries of Assam
- Conservation of endangered species
BOTANY PRACTICAL SYLLABUS (15 Marks)
| Component | Marks |
|---|---|
| Practical Performance | 12 |
| Practical Record Book | 03 |
| Total | 15 Marks |
Experiments Include
- Reproductive organs of flowers
- Pollination adaptations
- Pollen germination
- Pollen tube growth
- Study of fruits & seeds
- Mitosis in onion root tip
- Meiosis (permanent slide)
- Controlled pollination activities
- Soil pH & water holding capacity
- Plant adaptations (dry & aquatic)
- Population density & frequency
- Analogous & homologous organs
ZOOLOGY PRACTICAL SYLLABUS (15 Marks)
| Component | Marks |
|---|---|
| Practical Performance | 12 |
| Practical Record Book | 03 |
| Total | 15 Marks |
Experiments Include
- Gamete development (T.S. testis & ovary)
- Blastula study
- Mendelian inheritance using seeds
- Pedigree charts
- Study of disease-causing organisms
- Soil analysis
- Animal adaptations (dry & aquatic)
- Water sample study
- Air quality analysis
- Analogous & homologous organs
Important Links
| Class 12 Biology Syllabus PDF | Click Here |
| HS Class 12 Syllabus Home | Click Here |
| Official Website | Click Here |
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