CBSE Class 12 Biology Revision Notes

Introduction to CBSE Exam

Central Board of Secondary Education (CBSE) is one of the most reputed national level boards of education in India for private and public schools. CBSE board is controlled and managed by the Union Government of India. As a part of its initiative to provide quality education. CBSE also analyses and monitors its curriculum and activities by collecting feedback from different stakeholders. It gives a child-centred and holistic education programme to prepare students for college and subsequent careers.

CBSE Class 12 Biology Notes

Biology is a fascinating subject, and Biology revision notes come in handy to prepare you well for the Class 12 exams. CBSE Class 12 Biology Notes, designed by experts at Extramarks, cover the latest CBSE curriculum. These are some of the well-researched CBSE notes that let students understand the topic clearly. Students can refer to these Biology notes online or even click on the links provided on the Extramarks website. 

Students who study the revision notes generally score better as these notes cover the intricacies involved with solving any given problem. The revision notes are prepared by keeping the last few years’ question papers checked and updated according to the latest syllabus. It’s crucial to thoroughly know all the essential 16 topics of class 12 Biology to perform well in exams. CBSE students get a complete overview of all the chapters with relevant examples from these notes.

Chapter Wise Notes for Class 12 Biology

Class 12 Biology consists of a total of 16 significant chapters. CBSE Class 12 Biology Notes offer students a chapter-wise summary of the topics, essential points to remember, elaborate explanations of the critical points, and illustrations for better clarity of the chapter content. A panel of expert faculty at Extramarks has diligently prepared the chapter-wise notes according to the NCERT syllabus to ensure a clear and easy understanding of the concepts to score well in Board and other competitive exams.

Extramarks experts specially design the class 12 Biology notes with an in-depth understanding of the subject to help students complete their studies, thus clearing all the doubts that may arise while studying.

Chapter Topic
Chapter 1 Reproduction in Organisms
Chapter 2  Sexual Reproduction in Flowering Plants
Chapter 3 Human Reproduction
Chapter 4 Reproductive Health
Chapter 5 Principles of Inheritance and Variation
Chapter 6 Molecular Basis of Inheritance
Chapter 7 Evolution
Chapter 8 Human Health and Diseases
Chapter 9 Strategies for Enhancement in Food Production
Chapter 10 Microbes in Human Welfare
Chapter 11 Biotechnology Principles and Processes
Chapter 12 Biotechnology: and its Application
Chapter 13 Organisms and Populations
Chapter 14 Ecosystem
Chapter 15 Biodiversity and Conservation
Chapter 16 Environmental Issues

Chapter 1. Reproduction in Organisms

NCERT Solutions for Class 12 Biology Chapter No. 1 – Reproduction in Organisms is prepared by Extramarks subject experts and contains detailed answers for reference. All the textbook questions and exercises are answered here. Students are advised to refer to these notes and solutions to prepare for the examinations. The solutions provided in the NCERT Solutions for Class 12 are beneficial in enhancing conceptual knowledge. The CBSE Class 12 Biology Notes for this chapter explain the process of birth among plants and animals, which ensures species generation.

Chapter 2. Sexual Reproduction in Flowering Plants

Flowering plants reproduce sexually through a process called pollination. The flowers contain male sex organs called stamens and female sex organs called pistils. All the concepts covered in CBSE Class 12 Biology Notes are thoroughly explained in these NCERT Solutions. Also, this has been prepared by Extramarks subject experts with many years of teaching experience. 

Chapter 3. Human Reproduction

The process of giving birth to young ones who are identical to their parents is called human reproduction. The human reproductive system mainly consists of male and female reproductive organs. The notes are framed by subject experts and comprise detailed answers. You can get the links to CBSE Class 12 Biology Notes on the Extramarks website, where NCERT solutions, practice papers, and essential questions are available.

Chapter 4. Reproductive Health

According to the World Health Organisation, reproductive health means total well-being in reproduction’s physical, emotional, behavioural and social aspects. Healthy reproductive organs and behaviour are essential for the reproduction of healthy younger ones. CBSE Class 12 Biology Notes, which are entirely based on the updated CBSE curriculum, helps students prepare well for the exams. The subject matter experts at Extramarks have prepared the solutions in a step-by-step manner so students can get the concepts cleared at the root level.

Chapter 5. Principles of Inheritance and Variation

The process of passing characters from parent to progeny is called inheritance. It is the basis of heredity. The degree to which progeny differ from their parents is called variation. And human genetics is the scientific study of inherited human variation. Essential notes for CBSE Class 12 Biology Notes ‘Inheritance and Variation’ cover all the vital topics and concepts necessary for the exams. Students can strengthen their knowledge plus secure a good percentage in board exams by referring to these notes. 

Chapter 6. Molecular Basis of Inheritance

The molecular basis of inheritance involves the study of genes. The study includes DNA, DNA replication, DNA as genetic material, translation, transcription, genetic code, regulation of gene expression and many more. The molecule that carries genetic information in all living organisms and viruses used in functioning, growth, reproduction, and development is called DNA. CBSE Class 12 Biology Notes will help you achieve the desired scores by making your learning experience interesting, as every concept is explained in detail with diagrams.

Chapter 7. Evolution

Evolutionary biology studies the history of how life forms on earth. Evolution is the study of the various forms of life, their characteristics and the changes over several generations. Biologists use scientific theory to study the genetic variation in a population. The idea of evolution is based on the fact that all species are correlated and progressively differ with time. This chapter 7 forms an integral aspect of the CBSE curriculum. Students no longer need to prepare CBSE Class 12 Biology Notes on their own because Extramarks brings comprehensively drafted notes by renowned subject matter experts.

Chapter 8. Human Health and Diseases

According to the World Health Organisation, health is a state of an active and energetic condition including the physical, mental, and social well being. Good health is the overall welfare, not only the absence of illness. An individual can maintain good health by having balanced nutritional food and regular exercise. There are many factors like a poorly balanced diet, stress, anxiety, and intake of unhealthy food which affect health. CBSE Class 12 Biology Notes ensure that all the related topics and concepts are covered with a detailed explanation.

Chapter 9. Strategies for Enhancement in Food Production

The development and survival of all organisms depend on food. It is necessary to increase food production to feed the increasing population. Some of the strategies for enhancing food production are animal husbandry, plant breeding, fisheries, and bee-keeping. It also increases the production of high yielding Indian crops like wheat, sugarcane, millets and rice. Check CBSE Class 12 Biology Notes for the complete set of essential study material for Biology and solve the questions to check your understanding of the subject.

Chapter 10. Microbes in Human Welfare

They are multiple and include viruses, protozoa, bacteria, viroids, fungi, prions and other microscopic animals. Although pathogenic, They have a vital role to play in human welfare. Microbes could be quickly grown in laboratories for research and production in the industrial sector. Many commercial industries which produce alcoholic beverages, antibiotics and chemicals grow microbes. Household dairy products like curd, bread, cheese and fermented batter contain microbes. Check Extramarks for a complete set of introductory notes and study material for CBSE class 12 Biology, and solve the questions to check your understanding of the subject.

Chapter 11. Biotechnology Principles and Processes

The broad area of Biology which utilises both the technology and the application of living organisms and their components to develop, modify and produce valuable products for human development is called biotechnology. Genetic engineering and bioprocess engineering are the main principles of biotechnology. CBSE Class 12 Biology Notes contain all the essential concepts, biotechnology principles and processes for a deeper understanding of the subject. 

Chapter 12. Biotechnology and its Application

Biotechnology has been applied in diagnostics, therapeutics, genetically modified crops for agriculture, bioremediation, processed food, waste treatment, and energy production. The chapter is primarily theoretical. Students preparing for Board or competitive exams can consult CBSE Class 12 Biology Notes to better understand the topic.

Chapter 13. Organisms and Populations

The study of the interactions among various organisms and their environment is called ecology. Ecology is the branch of Biology that contains four levels of biological organisations:


  • Populations
  • Communities
  • Biomes
  • Organisms

One of the crucial chapters in NCERT Notes Class 12 Biology is chapter 13. For more clarity on this subject, refer to CBSE Class 12 Biology Notes, created by the experts on Extramarks.

Chapter 14. Ecosystem

An ecosystem is defined as a community where the living and nonliving organisms interact with each other and their surrounding physical environment. The ecosystem structure comprises two varied components, biotic and abiotic. Let us look at the ecosystem’s facility, function, and components in our CBSE Class 12 Biology Notes.

Chapter 15. Biodiversity and Conservation

A variety of animal and plant life on earth is biodiversity. You can explore this and its three types in detailed CBSE Class 12 Biology Notes prepared by Extramarks. The three types of biodiversity are:

  • Genetic
  • Ecological
  • Species Diversity

The Class 12 Biology NCERT Notes are available on Extramarks.

Chapter 16. Environmental Issues

The increase in human population, which demands a lot of food, clothing, housing, fuels, and vehicles, exerts a lot of pressure on land, water, air and other natural resources. This leads to environmental degradation, pollution, and other environmental issues. Let us thoroughly look at the environmental issues and their solutions in CBSE 12 Biology Notes.

For more information, refer CBSE Class 12 Biology Notes.

          CBSE Class 12 Biology Revision Notes               Important Questions for Class 12 Biology   

The CBSE Class 12 Biology Notes are designed to make concepts clear to the students with practical solutions, real-life examples and detailed chapters. 

CBSE Class 12 Biology – Distribution of Marks 

  1. The theory paper constitutes total – 70 marks
  2. Practicals constitute total – 30 marks

How Extramarks can Help Students with Class 12 Biology?

Extramarks help students improve their grades and get a sound understanding of concepts. The learning of the 12th Biology notes has been made effective and accessible with engaging and highly adaptive programs. The different study modules offered by Extramarks for CBSE Revision Notes will make your learning process simple and efficient. 

FAQs (Frequently Asked Questions)

1. Is 12th Biology complex?

The CBSE Class 12 Biology is moderately complex, but regular practice with Important Questions, CBSE Revision Notes, CBSE Previous Year Question Papers and Formulas on Extramarks gets easier.

2. How do I prepare for Biology class 12?

 Complete the basics and stick to the CBSE Syllabus. Refer Important Formulas, CBSE Sample Papers, CBSE extra question papers, and CBSE Previous Year Question Papers available on Extramarks website.