IISER Aptitude Test 2026 is around the corner. The exam officials have scheduled IAT 2026 on June 7, 2026 at multiple exam centres from 9 AM to 12 PM in online/CBT mode. As per the exam pattern, there will be questions from Mathematics, Physics, Chemistry and Biology sections. Candidates who have opted for PCM in their class 12, also need to prepare for the biology section to get a safe score to get admissions in IISERs, IISc, IACS and IITs.
Preparing for the IISER Aptitude Test 2026 Biology section requires much more than simply memorising NCERT chapters. Every year, the Biology portion of the exam tests students on conceptual clarity, application-based understanding, and analytical thinking through questions from Class 11 and 12 topics.
A smart preparation strategy focused on IAT 2026 Biology important topics can significantly improve accuracy and save valuable revision time during the final months of preparation. From Genetics, Human Physiology, Ecology, and Biotechnology to Plant Physiology and Evolution, certain chapters consistently dominate the Biology section of the exam.
In this SciAstra blog, candidates will get the IISER 2026 Biology Important Topics, chapter-wise weightage analysis, preparation tips, and expert strategies that can help aspirants maximise their score and strengthen their overall IAT 2026 preparation.
IAT 2026 Exam Pattern
If you are preparing for the Biology section, you must understand the overall structure of the exam question paper by going through the IAT 2026 exam pattern. The comprehensive overview of the IAT 2026 question paper is available below:
IAT 2026 Exam Pattern | |
Total Number of Questions | 60 Questions |
Sections | Four sections:
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Marking Scheme |
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Total Marks | 240 marks |
Test/Question Paper Language | Hindi and English |
Exam Duration | 180 minutes (3 hours) |
IAT 2026 Biology Important Topics & Chapters
Preparing for the Biology section of the IISER Aptitude Test is one of the smartest ways to improve your overall IAT 2026 score, especially for students coming from the PCB stream. Biology in IAT generally focuses on conceptual understanding, application-based learning, and NCERT-oriented questions from both Class 11 and Class 12 syllabi.
Candidates can check out the IAT 2026 Biology Important Topics from here:
IAT Biology Preparation 2026: Past Year Trend Analysis
Candidates appearing for the upcoming IAT 2026 exam must include the trend analysis of questions asked in the Biology section in their final stage of preparation. For candidates who do not have Biology in their Class 12 stream but still aim to achieve a good score in IAT 2026, mastering certain important topics from the Biology section becomes essential.
Now, the problem is that it is not possible for Mathematics students to cover all the Biology topics for IAT 2026. That is why a quick analysis of the IAT Biology past year trends plays an important role. SciAstra Mentors has provided a solution to this. Here is the complete IAT Biology past year trend analysis:
Biology | ||||||||||
Section | Chapters | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
Diversity | 1 | 1 | 1 | 1 | 1 | 1 | - | 1 | 1 | |
Morphology and Anatomy | 1 | - | 2 | 1 | 2 | 1 | 2 | 1 | - | |
Cell Biology and Biomolecules | Cell Biology | 2 | 2 | 1 | 1 | 1 | 1 | 1 | - | 1 |
Biomolecules | 1 | - | 1 | - | - | - | 2 | - | 1 | |
Plant Physiology | 2 | - | 1 | 2 | 3 | 2 | 1 | 2 | 2 | |
Human Physiology | 1 | 4 | 2 | 3 | 1 | 3 | 1 | 3 | 3 | |
Molecular Biology | Genetics | 1 | 1 | 1 | - | - | 3 | 1 | 1 | 2 |
Molecular Biology | - | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | |
Evolution | 1 | - | 1 | 1 | 1 | 1 | 1 | - | - | |
Human Health | Human Health & Disease and Microbes in Human Welfare | 2 | 2 | 1 | 1 | 1 | - | 1 | 1 | - |
Reproduction | 1 | - | 1 | 1 | - | - | 2 | 2 | 1 | |
Biotechnology | 1 | 2 | 1 | 1 | 2 | 1 | 1 | 2 | 1 | |
Ecology | 1 | 2 | 1 | 2 | 2 | 1 | 1 | 1 | 1 | |
Also Read: How to Prepare for IAT 2026 Biology Section
Top 5 Biology Topics for IAT 2026
Biology can become a scoring subject in the IISER Aptitude Test if students focus on the most important and high-weightage chapters. Every year, certain topics repeatedly ask in IAT 2026 Biology section, may due to conceptual importance and application-based nature.
For IAT 2026 aspirants, identifying these crucial areas can save preparation time and improve accuracy in the examination. This section will guide to through the top 5 Biology topics for IAT 2026 that students should prioritize during their preparation journey:
Important Topics | Concepts to Study |
Genetics | Principles of inheritance and variation: Mendel’s Laws of Inheritance, Inheritance of One Gene, Inheritance of Two Genes, Sex Determination, Mutation, Genetic Disorders. |
Molecular Biology | Molecular basis of inheritance: The DNA, The Search for Genetic Material, RNA World, Replication, Transcription, Genetic Code, Translation, Regulation of Gene Expression, Human Genome Project, DNA Fingerprinting. |
Biotechnology | Biotechnology: principles and processes: Principles of Biotechnology, Tools of Recombinant DNA Technology, Processes of Recombinant DNA Technology. Biotechnology and its application: Biotechnological Applications in Agriculture and Medicine, Transgenic Animals, Ethical Issues. |
Plant Physiology | Photosynthesis in higher plants: Photosynthesis, Early Experiments, Location of photosynthesis, Pigments involved in Photosy nthesis, Light Reaction, The Electron Transport, Synthesis and utilization of ATP and NADPH, The C4 Pathway, Photorespiration, Factors Affecting Photosynthesis. Respiration in plants: Do Plants Breathe? Glycolysis, Fermentation, Aerobic Respiration, The Respiratory Balance Sheet, Krebs/Citric acid cycle. Respiratory Quotient Plant growth and development: Growth, Differentiation, Dedifferentiation and Redifferentiation, Development, Plant Growth Regulators. |
Plant Reproduction | Morphology of flowering plants: The Root, The Stem, The Leaf, The Inflorescence, The Flower, The Fruit, The Seed, Semi-technical Description of a Typical Flowering Plant, Description of Some Important Families. Anatomy of flowering plants: The Tissue System, Anatomy of Dicotyledonous and Monocotyledonous Plants. |
Ecology | Organisms and populations: Populations, Logistic growth, Population interactions. Ecosystem Biodiversity and conservation: Biodiversity and Biodiversity conservation. |
IAT 2026 Biology Preparation Tips
Preparing for the Biology section of the IISER Aptitude Test requires a smart strategy, conceptual understanding, and continuous practice. Unlike board examinations, IAT Biology questions are more analytical, application-oriented, and designed to test a student’s scientific understanding. Therefore, students must focus not only on memorization but also on concept clarity and problem-solving ability. Here are some effective Biology preparation tips for IAT 2026 aspirants:
Build Strong NCERT Fundamentals
While preparing for the IISER entrance exam 2026, candidates primary focus should be NCERT Biology of Class 11 and Class 12. Most questions are directly or indirectly based on NCERT concepts, diagrams, terminology, and examples. Students should thoroughly read every chapter, including diagrams, tables, and summary points. Revising NCERT multiple times helps in strengthening conceptual understanding and factual retention.
Focus on High-Weightage Chapters
Not all Biology chapters carry equal importance in the examination. Students should prioritize frequently asked topics based on the IAT 2026 Preparation with trend analysis.
These chapters often contribute a major portion of the Biology section and should be revised repeatedly.
Practice Previous Year Questions
Solving previous year IAT questions is one of the best ways to understand the exam pattern and difficulty level. It helps students identify important topics, repeated concepts, and the type of analytical questions asked in the examination.
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Improve Conceptual Understanding
IAT Biology is not purely theoretical. Many questions test logical reasoning, data interpretation, and conceptual application. Students should understand the analytical behind biological processes rather than relying only on memorization. Flowcharts, concept maps, and self-made notes can help simplify complex topics.
Prepare Short Notes for Revision
Biology contains a large amount of information, making revision difficult during the final weeks. Students should prepare concise notes containing important definitions, diagrams, cycles, scientific names, and key points from each chapter. These notes become extremely useful during last-minute revision.
Attempt Mock Tests Regularly
Mock tests help students improve speed, accuracy, and time management. Attempting SciAstra IAT 2026 Mock Test helps in identifying weak areas that require additional practice. Aspirants should attempt section-wise tests first and gradually move to full-length mock tests under timed conditions.
Strengthen Weak Topics Gradually
Many PCM students find Biology challenging due to unfamiliar terminology and theoretical concepts. Instead of avoiding difficult chapters, students should learn them gradually through SciAstra Videos, notes, and repeated practice. Starting with easier topics first can help build confidence.
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IAT 2026 Preparation Books for Biology
Candidates can explore the list of books offered by Sciastra for the biology preparation of the IAT 2026 exam:
Book Name | Features | Purchase Link |
Mastering Combo- Class 11 Bookset
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Mastering Combo- Class 12 Bookset
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Mastering Combo- Class 11 and Class 12 Bookset
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IISER Aptitude Test Mock Book (2025-2026)
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