The Central Board of Secondary Education (CBSE) will hold the Class 12 Biology exam for the year 2026 on March 27, 2026 . The full CBSE Class 12 board examinations for 2026 will take place from February 17, 2026 , to April 10, 2026 . Students preparing for the Biology paper should focus on key topics to score well. The Biology exam is a 100-mark paper, with 70 marks for theory and 30 marks for practical work.
About 30% of the questions in the theory paper will be competency-based. These questions check a student's understanding and application of concepts, not just memory. The offline exam will last for 3 hours and will include different types of questions. These include Multiple Choice Questions (MCQs), case-based questions, short answer questions, and long answer questions.
CBSE Class 12 Biology 2026 Exam Pattern
Here is a quick look at the exam structure:
| Total Marks | 100 |
| Theory Exam Marks | 70 |
| Practical Exam Marks | 30 |
| Exam Duration | 3 hours |
| Question Types | MCQs, Case-based, Short Answer, Long Answer |
| Competency-based Questions | Around 30% |
Important Biology Topics for Class 12 Exam 2026
To prepare effectively for the CBSE Class 12 Biology exam, students should pay close attention to the following units and topics. These are considered essential and carry significant marks.
1. Genetics & Evolution (20 Marks)
- Molecular Basis of Inheritance: This part covers how genetic information is stored and used. Key areas include DNA replication (how DNA copies itself), transcription (how DNA makes RNA), translation (how RNA makes proteins), and the Lac Operon model (how genes are controlled).
- Principles of Inheritance: Students need to understand Mendel’s laws of inheritance. Practice solving problems using monohybrid and dihybrid crosses, often done with Punnett squares. Also study chromosomal disorders like Down's syndrome, which are caused by issues with chromosomes.
2. Reproduction (16 Marks)
- Sexual Reproduction in Flowering Plants: Focus on the process of double fertilization, which is unique to flowering plants. Understand how pollen and pistil interact. Also study what happens after fertilization, known as post-fertilization events, which lead to fruit and seed formation.
- Human Reproduction: Key topics include gametogenesis (the formation of sperm and egg cells – spermatogenesis and oogenesis), the menstrual cycle in females, and the early development of an embryo up to the blastocyst stage.
3. Biology in Human Welfare (12 Marks)
- Human Health and Diseases: This section deals with common diseases and the body's defense system. Learn about the life cycle of Plasmodium, the parasite that causes malaria. Understand different types of immunity (innate, which is natural, and acquired, which develops over time). Also study diseases like AIDS and Cancer.
4. Biotechnology (12 Marks)
- Principles and Applications: This unit covers modern biological techniques. Understand Polymerase Chain Reaction (PCR), a method to make many copies of DNA. Learn about recombinant DNA technology, which involves combining DNA from different sources. Study practical uses of biotechnology, such as Bt crops (genetically modified crops for pest resistance) and the production of human insulin.
5. Ecology (10 Marks)
- Ecosystem & Biodiversity: This section focuses on how living things interact with each other and their environment. Study ecological pyramids (like pyramids of numbers, biomass, and energy). Understand different ways populations interact, such as mutualism (both benefit) and parasitism (one benefits, one is harmed). Also, learn about strategies to conserve biodiversity and protect different species.
Students are advised to review these topics thoroughly. A strong understanding of these areas will help in preparing for the upcoming CBSE Class 12 Biology board exam in 2026.
