CBSE Class 12 2025 Biology preparation: Most repeated topics for Reproduction, Genetics and Evolution

Important topics in Biology for CBSE Class 12: The Central Board of Secondary Education (CBSE) has announced the schedule for the Class 12 Board Exams 2025. According to the released date sheet, the exams will take place from February 15 to April 4, 2024. The Class 12 Biology paper is scheduled for March 25, 2025.
Biology is a crucial subject for Class 12 students, particularly those aspiring to medical careers, as it plays a vital role in competitive exams like NEET. With proper preparation, students can excel not only in the board exams but also build a strong foundation for higher studies in Biology.
The CBSE Class 12 Biology paper this year will feature 50% knowledge and understanding-based questions, 30% application based questions, and 20% analysis and evaluation based questions, Chinar Banga, Biology Educator at Shiv Nadar School, Faridabad clarified. Below is a breakdown of the most repeated topics from three critical units, shared by Banga Reproduction, Genetics and Evolution, and Biology in Human Welfare.

CBSE Class 12 Biology Unit 1: Reproduction (16 Marks)

This unit delves into the biological processes of reproduction in both plants and humans, along with concepts related to reproductive health.

Sexual Reproduction in Flowering Plants

Key areas include microsporogenesis, megasporogenesis, and double fertilization. Students should focus on post-fertilization events such as endosperm and embryo development. Short-answer questions frequently cover apomixis, polyembryony, and seed dispersal mechanisms.

Human Reproduction

Questions often explore the structure and functions of reproductive organs, gametogenesis (with a focus on oogenesis), the menstrual cycle, and hormonal regulation. Analytical and assertion-reason questions are common in this chapter.

Reproductive Health

Topics like contraceptive methods, population explosion, and assisted reproductive technologies (ART) are typically presented as case-based or analysis-based questions.

CBSE Class 12 Biology Unit 2: Genetics and Evolution (20 Marks)

This unit focuses on the principles of inheritance, molecular biology, and evolutionary theories.

Principles of Inheritance and Variation

Be prepared for numerical problems on Mendelian inheritance, sex determination, and dihybrid crosses. Pedigree analysis is a frequently tested area. Application-based questions may cover incomplete dominance, codominance, and genetic disorders.

Molecular Basis of Inheritance

Both short- and long-answer questions appear on topics such as DNA replication, transcription, translation, genetic code, and mutations. Questions might also involve identifying codon sequences, translational units, and untranslated regions (UTRs).

Evolution

Numerical problems based on the Hardy-Weinberg principle are often included. Students should also prepare for questions on adaptive radiation, comparing theories of evolution, and understanding evolutionary concepts through contrasting ideas.

How can students score high in CBSE Class 12 Biology paper?

To score well, students must focus on understanding key concepts and practicing numerical problems and application-based questions. By systematically reviewing these topics and referring to sample papers, students can confidently aim for top marks in the CBSE Board Exams.