ISC Class 12 Biology Chapter-wise, Unit Wise Weightage 2026
Roshni Yadav22 Dec, 2025
ISC Class 12 Biology chapter-wise weightage 2026: This is based on five main units: Reproduction, Genetics and Evolution, Ecology and Environment, Biology and Human Welfare, and Biotechnology and Its Applications.
The theory paper carries 70 marks, and the practical exam carries 30 marks. The theory paper is divided into sections like MCQs, very short answers, short answers, and long answer questions. Each unit has specific marks assigned, helping students focus on important topics for better preparation. For practicals, students should carry their project and practical file.
Understanding the detailed marks distribution is essential for effective exam preparation. The ISC Class 12 Biology syllabus for 2025-26 divides the subject into five units.
This section summarizes the marks allocation for theory and practical exams, along with the question paper blueprint. Students can use this information to create a focused study strategy, giving more time to units with higher weightage.
ISC Class 12 Biology Weightage 2026 Theory Exam - Unit Wise
The theory paper holds 70 marks, which forms the major part of the overall assessment. The units and their respective weightage are crucial for students to note.
Reproduction carries the highest marks, followed closely by Genetics and Evolution, and Ecology and Environment. Biology and Human Welfare, and Biotechnology and Its Applications, also hold significant marks. This unit-wise weightage of the biology class 12 ISC 2026 helps identify priority areas
| ISC Class 12 Biology Weightage 2026 Theory Exam - Unit Wise | ||
|---|---|---|
| S. No. | Unit | Total Weightage |
| 1 | Reproduction | 16 Marks |
| 2 | Genetics and Evolution | 15 Marks |
| 3 | Biology and Human Welfare | 14 Marks |
| 4 | Biotechnology and Its Applications | 10 Marks |
| 5 | Ecology and Environment | 15 Marks |
| — | TOTAL | 70 Marks |
ISC Class 12 Biology Weightage 2026 Practical Exam
The practical examination contributes significantly with 30 marks. It tests a student's hands-on skills and understanding of experimental procedures. It is compulsory to pass both theory and practical papers to successfully pass ISC 12th Biology.
The weightage for the different components of the practical exam is clearly defined. This part of the ISC Class 12 Biology chapter wise weightage 2026 ensures a comprehensive assessment.
| ISC Class 12 Biology Weightage 2026 Practical Exam | |
|---|---|
| Assessment Type | Marks |
| Practical Exam (3 hours) | 15 |
| Project Work - Content, Introduction, Presentation (graphs, tables, charts, newspaper cuttings, diagrams, photographs, statistical analysis if relevant), Conclusion/Summary, Bibliography | 10 |
| Practical File - Each practical done in the academic year must be recorded in the practical file. All the practicals must be checked, signed, and dated by the subject teacher | 5 |
| Total Marks | 30 |
ISC Class 12 Biology Chapter-wise Weightage
| ISC Class 12 Biology Chapter-wise Weightage | ||
|---|---|---|
| Unit | Chapter Name | Approx. Marks |
| Unit I: Reproduction | Reproduction in Organisms | 3 |
| Sexual Reproduction in Flowering Plants | 4 | |
| Human Reproduction | 4 | |
| Reproductive Health | 3 | |
| Total – Unit I | 14 | |
| Unit II: Genetics & Evolution | Principles of Inheritance & Variation | 7 |
| Molecular Basis of Inheritance | 8 | |
| Evolution | 5 | |
| Total – Unit II | 20 | |
| Unit III: Biology & Human Welfare | Human Health & Diseases | 5 |
| Strategies for Enhancement in Food Production | 5 | |
| Microbes in Human Welfare | 4 | |
| Total – Unit III | 14 | |
| Unit IV: Biotechnology | Biotechnology: Principles & Processes | 5 |
| Biotechnology & Its Applications | 5 | |
| Total – Unit IV | 10 | |
| Unit V: Ecology & Environment | Organisms & Populations | 3 |
| Ecosystem | 3 | |
| Biodiversity & Conservation | 3 | |
| Environmental Issues | 3 | |
| Total – Unit V | 12 | |
ISC Class 12 Biology Question Paper Blueprint 2026
The question paper blueprint offers detailed insights into the format and types of questions students will face.
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The question paper blueprint provides a clear overview of the exam format and types of questions.
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Knowing the blueprint helps students plan their preparation and aim for better scores.
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It shows how questions are distributed across different sections, including:
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MCQs (Multiple Choice Questions)
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Very Short Answer Questions
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Short Answer Questions
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Long Answer Questions
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Question Paper Structure Rules
The theory paper lasts three hours and carries 70 marks. An extra 15 minutes is for reading the paper.
The paper has four sections: A, B, C, and D. Internal choices are provided in one question in Sections B, C, and D. Section A has one question with one or two marks each. Section B has seven questions, each carrying two marks.
Section C has seven questions, each carrying three marks. Section D has three questions, each carrying five marks. Drawing diagrams is necessary where needed.
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