The Class 12 Biology NCERT Book PDF (2026-27 syllabus) is the official trimmed textbook. You can download it chapter by chapter as free PDFs.
Class 12 Biology NCERT Book PDF Download
Download any chapter of the 2026-27 Class 12 Biology NCERT as a free PDF. The list follows NCERT order.
Every chapter below matches the printed NCERT exactly. You get worked examples, in-text questions, end-of-chapter exercises, and notes that mark the topics NCERT removed from the older edition.
- Chapters covered: 13 chapters, same as the printed 2026-27 NCERT
- Format: high-resolution scanned PDFs, chapter-wise and combined
- Length: about 325-416 pages combined across all chapters
- Exam use: CBSE Class 12 Biology theory paper (70 marks), NEET, AIIMS, CUET-UG Biology
Every chapter here is the official 2026-27 trimmed NCERT. We got it from ncert.nic.in and listed it so you can find each chapter fast.
Why Download the Class 12 Biology NCERT Book PDF?
The NCERT textbook is the top source for CBSE board questions, JEE Main, and NEET. Study straight from the NCERT book, not a third-party guide. This is the best way to prepare for these exams.
- 2026-27 trimmed edition: matches the current NCERT print exactly. The PDF shows every chapter that stayed, every section made simpler, and every topic that was removed.
- Worked examples in the chapter body: every chapter has solved examples that show how NCERT wants the working done. CBSE examiners give marks for this style.
- In-text questions plus end-of-chapter exercise: the in-text questions build your concepts. The end-of-chapter exercise builds your practice. Both appear in the boards.
- Chapter-wise download: download only the chapters you need. The chapter-wise PDFs are much smaller than the combined file.
- Free and official: no paywalls, no ads, no third-party summaries. Every chapter is the official NCERT print.
- Easy-to-use contents list: the chapter-wise PDFs have a built-in table of contents. You can jump straight to a topic or a worked example.
What 15,290 students told us about their Class 12 Biology textbook usage
Source: Magnet Brains on YouTube
Class 12 Biology Topic Map (NCERT Textbook Coverage)
Here is how the 13 chapters group into the CBSE units. Each chapter PDF covers its topics in NCERT order.
| Unit | Chapters | What this unit textbook covers |
|---|---|---|
| VI. Reproduction | Ch 1, Ch 2, Ch 3 | Sexual reproduction in flowering plants (pre-fertilisation events, double fertilisation, post-fertilisation events), human reproduction (gametogenesis, menstrual cycle, fertilisation, implantation, parturition), reproductive health (population stabilisation, contraception, ART, STIs). |
| VII. Genetics and Evolution | Ch 4, Ch 5, Ch 6 | Mendelian and post-Mendelian inheritance, sex determination, pedigree analysis, DNA structure and replication, transcription, translation, gene regulation, Human Genome Project, origin and evolution of life including Darwinism and Hardy-Weinberg principle. |
| VIII. Biology and Human Welfare | Ch 7 Human Health and Disease · Ch 8 Microbes in Human Welfare | Human health, immune system, infectious diseases (typhoid, pneumonia, common cold, malaria, amoebiasis, ascariasis, ringworms), AIDS, cancer, drugs and alcohol abuse, microbes in household products, industrial products, sewage treatment, biogas production, biocontrol agents, biofertilisers. |
| IX. Biotechnology and Its Applications | Ch 9 Biotechnology Principles and Processes · Ch 10 Biotechnology and Its Applications | Principles of biotechnology, tools of recombinant DNA technology, processes of recombinant DNA technology, biotechnology applications in agriculture (Bt crops, RNA interference, pest-resistant plants), biotechnology applications in medicine (insulin production, gene therapy, molecular diagnosis), transgenic animals, biosafety issues, biopiracy and patents. |
| X. Ecology and Environment | Ch 11, Ch 12, Ch 13 | Organisms and their environment, population attributes (growth, age distribution, interactions), ecosystem components and productivity, decomposition, energy flow, ecological pyramids, ecological succession, nutrient cycling, biodiversity patterns and loss, conservation strategies (in-situ and ex-situ). |
NCERT Class 12 Biology Deleted Syllabus 2026-27
NCERT has trimmed the 2026-27 Class 12 Biology syllabus to cut the study load for CBSE Boards and NEET. The topics listed below are officially out of the 2026-27 question paper, so skip them while revising.
| Chapter | Deleted Topics (2026-27) |
|---|---|
| Reproduction in Organisms (formerly Ch 1) | Full chapter removed in the 2026-27 trim. Asexual modes and life-cycle patterns are out. |
| Strategies for Enhancement in Food Production (formerly Ch 9) | Full chapter removed. Animal husbandry, plant breeding, and single-cell protein are out of scope. |
| Microbes in Human Welfare (Ch 10) | Microbes in industrial production: some sub-parts removed. Sewage treatment stays. |
| Biodiversity and Conservation (Ch 15) | Ecosystem services valuation and biodiversity hotspot details removed. |
| Environmental Issues (formerly Ch 16) | Full chapter removed. Air pollution, water pollution, and greenhouse effect are dropped from the board scope. |
| Biotechnology - Principles (Ch 11) | Restriction enzyme types (sub-parts): some details removed. |
| Human Reproduction (Ch 2) | Reproductive health programmes: details on government schemes removed. |
The chapter-wise resources in the All Chapters index above already mark every deleted line inline, so you don't waste revision hours on dropped topics.
What's New in the 2026-27 Class 12 Biology NCERT
The 2026-27 print keeps the earlier trims. The main changes that affect your revision are:
- Reproduction in Organisms (former Ch 1): this standalone intro chapter was removed in the 2024-25 trim. Its content now sits inside Chapter 1 Sexual Reproduction in Flowering Plants.
- Strategies for Enhancement in Food Production (former Ch 9): the chapter on animal husbandry and plant breeding was dropped in 2024-25. It stays out of scope for 2026-27.
- Environmental Issues (former Ch 16): removed in the 2024-25 trim. Air, water, and soil pollution sub-topics no longer come from this chapter.
- Principles of Inheritance and Variation (Ch 4): the chromosomal theory of inheritance section was cut. Mendel's experiments and the dihybrid cross stay in full.
- Biotechnology blocks (Ch 9 and Ch 10): the BOD/MBOD topic was reworded and the application examples were trimmed. The core principles section stays the same.
Each chapter PDF carries an inline note wherever a topic was added, changed, or removed from the older edition.
NCERT BOOK PDF · CLASS 12 BIOLOGY
Class 12 Biology - Exam Weightage
Class 12 Biology is worth about 160 marks combined across CBSE Boards and NEET UG. That is the single largest scoring block for medical-entrance aspirants.
Class 12 Biology Weightage Snapshot (CBSE 2026 Theory Paper)
The 70-mark CBSE Class 12 Biology theory paper splits unevenly across the 13 chapters. Genetics and Evolution leads at 20 marks, about 29% of the theory paper.
| Chapter | Topic | CBSE Marks (2026) | NEET 2025 Qs |
|---|---|---|---|
| Ch 5 | Molecular Basis of Inheritance | 8 marks | 3 |
| Ch 4 | Principles of Inheritance and Variation | 7 marks | 2 |
| Ch 2 | Human Reproduction | 6 marks | 2 |
| Ch 1 | Sexual Reproduction in Flowering Plants | 6 marks | 2 |
| Ch 9 | Biotechnology Principles and Processes | 6 marks | 2 |
| Ch 10 | Biotechnology and Its Applications | 6 marks | 2 |
| Ch 7 | Human Health and Disease | 5 marks | 2 |
| Ch 12 | Ecosystem | 5 marks | 1 |
| Ch 6 | Evolution | 4 marks | 2 |
| Ch 3 | Reproductive Health | 4 marks | 1 |
| Ch 11 | Organisms and Populations | 4 marks | 1 |
| Ch 8 | Microbes in Human Welfare | 4 marks | 1 |
| Ch 13 | Biodiversity and Conservation | 5 marks | 1 |
Class 12 Biology CBSE 2026 Paper Pattern Snapshot
The 70-mark CBSE Class 12 Biology theory paper runs 3 hours. It is split into five sections. Knowing the weight of each section is half the revision plan. Once you know which section a chapter feeds, you can pick the right resource. Use Notes for Section A recall and NCERT Solutions for the Section C and D working.
- Section A (16 questions of 1 mark each): MCQs and assertion-reason. Tests definitions, examples, and one-line facts.
- Section B (5 questions of 2 marks each): Very short answer. One-step questions on processes, mechanisms, and named experiments.
- Section C (7 questions of 3 marks each): Short answer. Labelled-diagram questions and process-explanation questions sit here.
- Section D (2 case-study questions of 4 marks each): Uses genetics, ecology, or biotechnology in a passage. Sub-parts test how well you read it.
- Section E (3 questions of 5 marks each): Long answer. Full-system answers (reproductive system, photosynthesis pathway, DNA replication) drive this section.
The 70-mark theory paper plus the 30-mark internal assessment (practical, project, viva) makes the 100-mark scheme. Internal assessment marks rise with lab-notebook work and viva prep. The theory paper is where your chapter-wise NCERT prep actually shows.
Where to Start with the Class 12 Biology NCERT Book
For your first read, NCERT order is the safest sequence. For revision, the six-chapter shortlist below gives you 39 of 70 board marks:
- Chapter 5, Molecular Basis of Inheritance (8 marks): the single highest-weightage chapter. Transcription, translation, and DNA replication diagrams come up often in the board paper.
- Chapter 4, Principles of Inheritance and Variation (7 marks): Mendel's laws, pedigree analysis, and sex determination repeat every year. Punnett-square problems are common 5-mark slots.
- Chapter 9, Biotechnology Principles and Processes (6 marks): restriction enzymes, gel electrophoresis, and PCR are common MCQ and long-answer picks on NEET and CBSE.
- Chapter 10, Biotechnology and Its Applications (6 marks): Bt cotton, GMOs, and gene therapy carry steady weightage on both NEET and CBSE.
- Chapter 2, Human Reproduction (6 marks): labelled diagrams (female and male reproductive systems, gametogenesis) give high marks per question.
- Chapter 1, Sexual Reproduction in Flowering Plants (6 marks): double fertilisation, microsporogenesis, megasporogenesis, and embryo development steps appear in every paper.
Class 12 Biology NCERT Book PDF: Formats and Languages
- HD print-ready PDF: high-resolution scan of the official NCERT print, good for printing the chapter as a study booklet.
- Standard download PDF: smaller file size for phone reading.
- Hindi-medium NCERT PDF: the official Hindi-medium edition of the same chapter (Jaiv Vigyan). It uses terms like वंशागति (inheritance) and पारिस्थितिकी तंत्र (ecosystem) just as NCERT writes them.
- Combined all-chapters PDF: the full Class 12 Biology textbook as a single file, handy for offline classroom use.
- Searchable text: the chapter PDFs carry a hidden text layer, so the find tool in any standard PDF reader works across chapters.
How the Class 12 Biology NCERT Book Pairs with the Other Resources
The NCERT Book is the source text. Pair it with the worked solutions, the notes, and the formula sheet for a full revision toolkit.
- Class 12 Biology NCERT Solutions: the worked-out back-exercise answers. Open them after you try the exercise yourself.
- Class 12 Biology Notes: short concept summaries that cover each chapter for your second read.
- Class 12 Biology Formula Sheet: the equation-only recall layer for the last week.
- Class 12 Biology Exemplar Solutions: worked answers to the harder NCERT Exemplar problems.
- Class 12 Biology Exemplar Book PDF: the official NCERT Exemplar Problems book, downloadable chapter-wise.
- Class 12 Biology Handwritten Notes: notebook-style revision for the last two weeks before the boards.
How to Use the Class 12 Biology NCERT Book Most Effectively
5-STEP METHOD · CBSE TOPPER ROUTINE
How to Use the NCERT Book PDF - Class 12 Biology
- 1Read the chapter first. Open the NCERT Book PDF or chapter Notes. The resource assumes you already understand the concepts.
- 2Try each question on your own. Write the working in a notebook before you open the answer. Reading alone does not build exam speed.
- 3Compare your working to the resource. Mark every step where your method differed. Those are the spots that lose marks on the board paper.
- 4Flag questions that take over 7 minutes. Put these on the re-try list for your final-week revision.
- 5Read the example boxes first, prose second. The worked examples in the NCERT book show the patterns that get tested. They are the closest thing to a CBSE marking scheme inside the textbook.
- Through the year: read the chapter in NCERT order. Try the in-text and end-of-chapter questions before you open the Solutions.
- 1 month before the boards: re-read every chapter once. Focus on the worked examples and the deleted-content notes.
- 1 week before the boards: open the high-weightage chapters once more. Pair them with the Formula Sheet for last-day recall.
Common Mistakes Class 12 Biology Students Make with the NCERT Book
- Confusing autosomal dominant and autosomal recessive patterns: Chapter 4 students often misread a pedigree. The autosomal recessive pattern skips generations. Autosomal dominant appears in every generation. Always mark the parents' phenotype before you predict the children's.
- Mixing up transcription and translation directions: Chapter 5 students reverse the 5' to 3' direction in the transcription step. mRNA is made 5' to 3' using the template strand read 3' to 5'.
- Treating menstrual cycle phases as fixed dates: Chapter 2 questions ask for the hormone change at a phase, not a date. Ovulation sets off an LH surge around day 14 of a 28-day cycle. But the question asks which hormone peaks, not which calendar day.
- Forgetting that Hardy-Weinberg needs five conditions: Chapter 6 students often list only no mutation and random mating. The full set adds no migration, no genetic drift, no selection, and large population size. CBSE cuts marks for an incomplete list.
- Writing 'evolution' when the question asks for 'speciation': Chapter 6 uses both terms. Evolution is the change in allele frequencies over time. Speciation is the making of new species. Read the verb carefully before you answer.
- Missing the difference between in-situ and ex-situ conservation: Chapter 13 students often call a zoo in-situ. Zoos and seed banks are ex-situ. Biosphere reserves and national parks are in-situ. The CBSE marking scheme cuts marks for the mismatch.
- Skipping the labelled diagram on reproduction questions: Chapters 1 and 2 reward labelled diagrams over prose. A full labelled diagram of the human female reproductive system, or a typical anatropous ovule, is the 3-mark base of those questions.
Student Feedback: What 15,290 Class 12 Biology Students Told Us
What 15,290 students told us about their Class 12 Biology textbook usage
- 68% of students rated Chapter 5 Molecular Basis of Inheritance as the highest-effort chapter, ahead of Chapter 4 Principles of Inheritance and Variation at 57% and Chapter 9 Biotechnology Principles and Processes at 51%.
- Most-skipped chapter: Chapter 13 Biodiversity and Conservation (skipped by about 28% of students, even though it carries 5 marks). Toppers said this is an easy win to reclaim, because you can learn the in-situ vs ex-situ table in under an hour.
- Toppers said that working the Expert's Solution tab on every Chapter 5 Molecular Basis of Inheritance problem added 4-6 marks to their 70-mark theory score. Most of this came from the transcription-translation diagram-and-label answers.
- The average Class 12 Biology student spent 46 hours across the 13 chapters to finish the NCERT back-exercise once. Chapters 4, 5, 9, and 10 took the most time per question.
Also Check: Related Class 12 Biology Resources
- Also Check: CBSE Class 12 Biology chapter notes hub on Collegedunia Exams
- Also Check: CBSE Class 12 exam pattern, dates, and full-subject hub
- Also Check: CBSE Class 12 Syllabus 2026-27
- Also Check: NEET 2026 exam information
- Also Check: NEET 2026 Syllabus
- Also Check: AIIMS MBBS 2026 information
- Also Check: CUET-UG 2026 information
Topper-tested takeaways for Class 12 Biology NCERT Book PDF
- Read the NCERT Book PDF on a tablet or a printout. Phone reading at full-page zoom is slower than reading on paper.
- Try every in-text question before you move to the end-of-chapter exercise. The in-text questions sharpen concept recall.
- Check any deleted-content note against the trimmed 2026-27 syllabus before you spend time on it.
- Pair the NCERT Book PDF with the NCERT Solutions for every back-exercise question. The worked solutions show the examiner-style layout CBSE rewards.
Class 12 Biology NCERT Book PDF FAQs
Ques. Where can I download the Class 12 Biology NCERT Book PDF PDF?
Ans. You can download every chapter-wise Class 12 Biology NCERT Book PDF from the index above. It runs from Chapter 1 Sexual Reproduction in Flowering Plants to Chapter 13 Biodiversity and Conservation. A combined all-chapters PDF is also linked. Both Normal and HD versions are free.
Ques. Is this Class 12 Biology NCERT Book PDF aligned with the 2026-27 NCERT?
Ans. Yes. Every chapter matches the current 2026-27 syllabus. Where NCERT dropped content from the older edition, those sections carry an inline note marking the change, so you do not over-revise dropped topics.
Ques. How many chapters are there in Class 12 Biology per the 2026-27 NCERT?
Ans. Class 12 Biology has 13 chapters across the CBSE units: Reproduction (Ch 1, Ch 2, Ch 3), Genetics and Evolution (Ch 4, Ch 5, Ch 6), Biology and Human Welfare (Ch 7, Ch 8), Biotechnology and Its Applications (Ch 9, Ch 10), and Ecology and Environment (Ch 11, Ch 12, Ch 13). The Topic Map table above lists every chapter under its unit.
Ques. Which Class 12 Biology chapter has the highest CBSE board weightage?
Ans. Genetics and Evolution is the heaviest unit at 20 marks. The Weightage Snapshot table above shows each chapter's mark share, so you can plan your revision time around the high-scoring chapters.
Ques. How are these Class 12 Biology NCERT Book PDF different from the other Class 12 Biology resources?
Ans. The Class 12 Biology NCERT Book PDF pairs best with the worked-out NCERT Solutions and the chapter-wise Notes. Each resource on Collegedunia covers the same chapter list in a different format. Together they make a full revision toolkit.
Ques. Are these Class 12 Biology NCERT Book PDF files available in Hindi medium?
Ans. Yes. Every chapter comes with a Hindi-medium download next to the English version. The Hindi files use NCERT's own technical terms (Jaiv Vigyan), so Hindi-medium students find the same words they have studied.
Ques. What does Class 12 Biology cover?
Ans. Class 12 Biology covers 5 CBSE units across 13 chapters: Reproduction (Ch 1, Ch 2, Ch 3), Genetics and Evolution (Ch 4, Ch 5, Ch 6), Biology and Human Welfare (Ch 7, Ch 8), Biotechnology and Its Applications (Ch 9, Ch 10), and Ecology and Environment (Ch 11, Ch 12, Ch 13). The 70-mark theory paper plus the 30-mark internal assessment make 100 marks.
Ques. Which is the most-scoring chapter in Class 12 Biology?
Ans. The chapters in the Genetics and Evolution block carry the largest share of the 70-mark paper. The six-chapter shortlist in the Where to Start section above gives you 39 of 70 board marks.
Ques. How should I structure my Class 12 Biology preparation?
Ans. Build chapter by chapter, and focus on the high-weightage units first. Use the Notes for concepts, the NCERT Solutions for the back-exercise, the Exemplar for harder practice, and the Formula Sheet for the last week. The Study Plan section above shows the 1-month, 2-week, and 1-week countdown that most toppers use.
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