TN State Board · Class 12
Biology Complete Guide
Syllabus, official resources, chapter guides, textbook solutions, question bank, model papers, revision plan, exam tips, and FAQs.
Chapters
22
Published Guides
59
Chapter Guides
26/22
Practice Resources
10
📝 Textbook Exercise Solutions — Chapter-wise
MCQ, short answers, long answers, and numericals with full worked solutions
Syllabus and Official Resources
Official-first1 syllabus focus area with Tamil Nadu textbook resources as the primary source.
View sectionTextbook Exercise Solutions
LiveExercise workflow pages are live for answer-writing and correction practice.
View sectionImportant Questions
Ready5 question patterns are listed for one-mark, short-answer, and long-answer practice.
View sectionExam Tips
Subject-specificExam guidance focuses on biology presentation, keywords, time use, and common mistakes.
View sectionFAQs
In guidesFAQs are included inside individual guides so answers stay close to the exact chapter or resource.
View sectionSyllabus Roadmap
- Combined Bio Botany and Bio Zoology coverage for reproduction, genetics, biotechnology, ecology, plant breeding, human reproduction, health, microbes, evolution, biodiversity, and environmental issues.
Official Books
Use official Tamil Nadu textbook resources first, then study with KalviGavani chapter guides.
Open TN Textbook SourceChapter Dashboard
26/22 chapter guides published
Bio Botany · Chapter 1
Bio Botany - Asexual and Sexual Reproduction in Plants
Bio Botany · Chapter 2
Bio Botany - Classical Genetics
Bio Botany · Chapter 3
Bio Botany - Chromosomal Basis of Inheritance
Bio Botany · Chapter 4
Bio Botany - Principles and Processes of Biotechnology
Bio Botany · Chapter 5
Bio Botany - Plant Tissue Culture
Bio Botany · Chapter 6
Bio Botany - Principles of Ecology
Bio Botany · Chapter 7
Bio Botany - Ecosystem
Bio Botany · Chapter 8
Bio Botany - Environmental Issues
Bio Botany · Chapter 9
Bio Botany - Plant Breeding
Bio Botany · Chapter 10
Bio Botany - Economically Useful Plants and Entrepreneurial Botany
Bio Zoology · Chapter 11
Bio Zoology - Reproduction in Organisms
Bio Zoology · Chapter 12
Bio Zoology - Human Reproduction
Bio Zoology · Chapter 13
Bio Zoology - Reproductive Health
Bio Zoology · Chapter 14
Bio Zoology - Principles of Inheritance and Variation
Bio Zoology · Chapter 15
Bio Zoology - Molecular Genetics
Bio Zoology · Chapter 16
Bio Zoology - Evolution
Bio Zoology · Chapter 17
Bio Zoology - Human Health and Diseases
Bio Zoology · Chapter 18
Bio Zoology - Microbes in Human Welfare
Bio Zoology · Chapter 19
Bio Zoology - Applications of Biotechnology
Bio Zoology · Chapter 20
Bio Zoology - Organisms and Populations
Bio Zoology · Chapter 21
Bio Zoology - Biodiversity and Its Conservation
Bio Zoology · Chapter 22
Bio Zoology - Environmental Issues
Question Bank
- Definitions and biological terms
- Labelled diagrams
- Genetics and biotechnology reasoning
- Process explanations
- Public exam application questions
Model Papers
- After each unit, solve a short unit test.
- After every major section, revise mistakes before moving to the next unit.
- In the final month, write one full subject model paper every week.
- Use the last revision cycle only for weak topics, formulae, diagrams, grammar rules, maps, or key terms.
Revision Plan
- Week 1: Read the official textbook and mark glossary, formulae, dates, rules, and diagrams.
- Week 2: Complete textbook exercises and correct repeated mistakes.
- Week 3: Practise important questions, unit tests, diagrams, maps, grammar, and writing formats.
- Week 4: Write model papers and revise only the mistake notebook.
Published Chapter Guides
Guide
Tamil Nadu Class 12 Biology — Genetics and Heredity Notes & Important Questions
Complete Samacheer Kalvi Class 12 Biology Genetics guide — Mendel's laws, monohybrid and dihybrid crosses, codominance, linkage, mutations, and board exam Q&A.
22 May 2026
Guide
Tamil Nadu Class 12 Biology — Molecular Biology and DNA Notes
Samacheer Kalvi Class 12 Biology DNA structure, Watson-Crick model, DNA replication, transcription, translation, genetic code, lac operon — board exam and NEET guide.
22 May 2026
Guide
Tamil Nadu Class 12 Biology — Plant Physiology Notes & Important Questions
Complete Samacheer Kalvi Class 12 Biology Plant Physiology guide — photosynthesis light and dark reactions, C3 C4 CAM plants, plant respiration, transpiration, phytohormones, board exam Q&A.
22 May 2026
Guide
Tamil Nadu Class 12 Biology — Human Reproduction Notes & Important Questions
Complete Samacheer Kalvi Class 12 Biology Human Reproduction guide — male and female reproductive systems, menstrual cycle, gametogenesis, fertilisation, embryonic development, board exam Q&A.
22 May 2026
chapter-guide
Tamil Nadu Class 12 Biology Evolution Notes — Samacheer Kalvi
Complete Bio Zoology notes on Evolution for Tamil Nadu Class 12 Biology with evidence, Darwinism, natural selection, Hardy-Weinberg principle, and exam questions.
17 May 2026
chapter-guide
Tamil Nadu Class 12 Biology Molecular Genetics Notes — Samacheer Kalvi
Complete Bio Zoology notes on Molecular Genetics for Tamil Nadu Class 12 Biology with DNA structure, replication, transcription, translation, genetic code, and exam questions.
17 May 2026
chapter-guide
Tamil Nadu Class 12 Biology Inheritance and Variation Notes — Samacheer Kalvi
Complete Bio Zoology notes on Principles of Inheritance and Variation for Tamil Nadu Class 12 Biology with Mendel laws, crosses, sex determination, pedigree basics, and exam questions.
17 May 2026
chapter-guide
Tamil Nadu Class 12 Biology Human Reproduction Notes — Samacheer Kalvi
Complete Bio Zoology notes on Human Reproduction for Tamil Nadu Class 12 Biology with male and female systems, gametogenesis, menstrual cycle, fertilisation, and exam questions.
16 May 2026
chapter-guide
Tamil Nadu Class 12 Biology Reproduction in Organisms Notes — Samacheer Kalvi
Complete Bio Zoology notes on Reproduction in Organisms for Tamil Nadu Class 12 Biology with asexual and sexual reproduction, life cycles, comparisons, and exam questions.
16 May 2026
chapter-guide
Tamil Nadu Class 12 Biology Reproductive Health Notes — Samacheer Kalvi
Complete Bio Zoology notes on Reproductive Health for Tamil Nadu Class 12 Biology with contraception, STIs, infertility, ART, awareness, and exam questions.
16 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Asexual and Sexual Reproduction in Plants
Samacheer Kalvi Class 12 Biology Bio Botany - Asexual and Sexual Reproduction in Plants guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Chromosomal Basis of Inheritance
Samacheer Kalvi Class 12 Biology Bio Botany - Chromosomal Basis of Inheritance guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Classical Genetics
Samacheer Kalvi Class 12 Biology Bio Botany - Classical Genetics guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Economically Useful Plants and Entrepreneurial Botany
Samacheer Kalvi Class 12 Biology Bio Botany - Economically Useful Plants and Entrepreneurial Botany guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Ecosystem
Samacheer Kalvi Class 12 Biology Bio Botany - Ecosystem guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Environmental Issues
Samacheer Kalvi Class 12 Biology Bio Botany - Environmental Issues guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Plant Breeding
Samacheer Kalvi Class 12 Biology Bio Botany - Plant Breeding guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Plant Tissue Culture
Samacheer Kalvi Class 12 Biology Bio Botany - Plant Tissue Culture guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Principles and Processes of Biotechnology
Samacheer Kalvi Class 12 Biology Bio Botany - Principles and Processes of Biotechnology guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Botany - Principles of Ecology
Samacheer Kalvi Class 12 Biology Bio Botany - Principles of Ecology guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Zoology - Applications of Biotechnology
Samacheer Kalvi Class 12 Biology Bio Zoology - Applications of Biotechnology guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Zoology - Biodiversity and Its Conservation
Samacheer Kalvi Class 12 Biology Bio Zoology - Biodiversity and Its Conservation guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Zoology - Environmental Issues
Samacheer Kalvi Class 12 Biology Bio Zoology - Environmental Issues guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Zoology - Human Health and Diseases
Samacheer Kalvi Class 12 Biology Bio Zoology - Human Health and Diseases guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Zoology - Microbes in Human Welfare
Samacheer Kalvi Class 12 Biology Bio Zoology - Microbes in Human Welfare guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
chapter-guide
Tamil Nadu Class 12 Biology: Bio Zoology - Organisms and Populations
Samacheer Kalvi Class 12 Biology Bio Zoology - Organisms and Populations guide with summary, textbook workflow, important questions, practice tasks, common mistakes, and revision checklist.
10 May 2026
Exercise Solutions
Chapter-wise textbook answers with a quick path back to notes.
Asexual and Sexual Reproduction in Plants Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 1 Asexual and Sexual Reproduction in Plants exercise solutions with key diagrams, definitions, short answers, and exam tips.
25 May 2026
Classical Genetics Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 2 Classical Genetics exercise solutions — Mendel's laws, dihybrid cross, codominance, linkage, and exam problem-solving steps.
25 May 2026
Chromosomal Basis of Inheritance Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 3 Chromosomal Basis of Inheritance exercise solutions — sex determination, sex-linked inheritance, chromosomal disorders, and exam tips.
25 May 2026
Molecular Genetics Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 4 Molecular Genetics exercise solutions — DNA structure, replication, transcription, translation, gene regulation, and exam tips.
25 May 2026
Environmental Issues Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 5 Environmental Issues (Botany) exercise solutions — pollution, deforestation, conservation, biodiversity, and exam tips.
25 May 2026
Principles of Ecology Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 6 Principles of Ecology exercise solutions — ecosystem components, energy flow, ecological pyramids, biogeochemical cycles, and exam tips.
25 May 2026
Plant Tissue Culture Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 7 Plant Tissue Culture exercise solutions — totipotency, explant, callus, somatic embryogenesis, micropropagation, and exam tips.
25 May 2026
Principles and Processes of Biotechnology Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 8 Principles and Processes of Biotechnology exercise solutions — recombinant DNA, restriction enzymes, PCR, gel electrophoresis, and exam tips.
25 May 2026
Plant Breeding and Crop Improvement Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 9 Plant Breeding and Crop Improvement exercise solutions — hybridisation, mutation breeding, green revolution, biofortification, and exam tips.
25 May 2026
Economically Useful Plants Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 10 Economically Useful Plants exercise solutions — food crops, fibres, timber, medicinal plants, and exam tips.
25 May 2026
Reproduction in Organisms Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 11 Reproduction in Organisms exercise solutions — types of reproduction, asexual modes, sexual reproduction events, and exam tips.
25 May 2026
Human Reproduction Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 12 Human Reproduction exercise solutions — male and female reproductive systems, gametogenesis, menstrual cycle, fertilisation, and exam tips.
25 May 2026
Reproductive Health Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 13 Reproductive Health exercise solutions — contraception, STDs, infertility, ART (IVF, GIFT, ICSI), and exam tips.
25 May 2026
Principles of Inheritance and Variation Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 14 Principles of Inheritance and Variation exercise solutions — Mendel's laws, blood groups, genetic disorders, and exam tips.
25 May 2026
Molecular Genetics Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 15 Molecular Genetics (Zoology) exercise solutions — Human Genome Project, DNA fingerprinting, gene therapy, and exam tips.
25 May 2026
Evolution Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 16 Evolution exercise solutions — theories of evolution, natural selection, Hardy-Weinberg law, evidences, and exam tips.
25 May 2026
Human Health and Diseases Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 17 Human Health and Diseases exercise solutions — immunity types, pathogens, cancer, drugs of abuse, and exam tips.
25 May 2026
Microbes in Human Welfare Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 18 Microbes in Human Welfare exercise solutions — industrial microbes, biogas, bioremediation, antibiotics, and exam tips.
25 May 2026
Biotechnology and its Applications Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 19 Biotechnology and its Applications exercise solutions — transgenic organisms, Bt crops, insulin production, gene therapy, bioethics, and exam tips.
25 May 2026
Organisms and Populations Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 20 Organisms and Populations exercise solutions — population attributes, growth models, ecological interactions, and exam tips.
25 May 2026
Biodiversity and Conservation Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 21 Biodiversity and Conservation exercise solutions — types of biodiversity, threats, in situ and ex situ conservation, hotspots, and exam tips.
25 May 2026
Environmental Issues Exercise Solutions
Tamil Nadu Class 12 Biology Chapter 22 Environmental Issues (Zoology) exercise solutions — pollution effects on animals, biomagnification, solid waste, radioactive pollution, and exam tips.
25 May 2026
Practice Resources
unit-test
Tamil Nadu Class 12 Biology Term 2 Unit Test — Samacheer Kalvi
Class 12 Biology Term 2 practice test for Tamil Nadu State Board students with questions from inheritance, molecular genetics, evolution, health, and biotechnology.
17 May 2026
unit-test
Tamil Nadu Class 12 Biology Term 1 Unit Test — Samacheer Kalvi
Class 12 Biology Term 1 practice test for Tamil Nadu State Board students with questions from reproduction, inheritance, and molecular genetics.
16 May 2026
revision-plan
Tamil Nadu Class 12 Biology 30-Day Revision Plan — Samacheer Kalvi
Class 12 Biology 30-day revision plan for Tamil Nadu State Board students with weekly revision cycles, term-wise planning, model-paper practice, and mistake correction.
10 May 2026
drill-practice
Tamil Nadu Class 12 Biology Biology Diagram Bank — Samacheer Kalvi
Class 12 Biology biology diagram bank for Tamil Nadu State Board students with labelled diagrams, parts, functions, and neat presentation practice.
10 May 2026
question-bank
Tamil Nadu Class 12 Biology Biology Key Terms Bank — Samacheer Kalvi
Class 12 Biology biology key terms bank for Tamil Nadu State Board students with botany and zoology definitions, differences, and process keywords.
10 May 2026
model-paper
Tamil Nadu Class 12 Biology Model Paper 1 — Samacheer Kalvi
Class 12 Biology model paper 1 for Tamil Nadu State Board students with term-wise sections, written answer practice, and time management.
10 May 2026
model-paper
Tamil Nadu Class 12 Biology Model Paper 2 — Samacheer Kalvi
Class 12 Biology model paper 2 for Tamil Nadu State Board students with term-wise sections, written answer practice, and time management.
10 May 2026
question-bank
Tamil Nadu Class 12 Biology Question Bank — Samacheer Kalvi
Class 12 Biology question bank for Tamil Nadu State Board students with chapter-wise one-mark, short-answer, long-answer, and term revision practice.
10 May 2026
unit-test
Tamil Nadu Class 12 Biology Term 3 Unit Test — Samacheer Kalvi
Class 12 Biology term 3 unit test for Tamil Nadu State Board students with term-wise chapter checks, short tests, and correction checklist.
10 May 2026
textbook-solutions
Tamil Nadu Class 12 Biology Biology Textbook Solutions Map — Samacheer Kalvi
Class 12 Biology biology textbook solutions map for Tamil Nadu State Board students with chapter-wise exercise workflow for Bio Botany and Bio Zoology.
10 May 2026
