Tamil Nadu (TNBSE)Class 12Subject library

Tamil Nadu (TNBSE) Class 12 Biology

Chapter-wise notes, previous year papers, sample papers and Q&A for Tamil Nadu (TNBSE) Class 12 biology — free, syllabus-aligned, exam-ready.

12 chapters~226 min read totalFree · printable

Chapters

12 chapters — sequenced for revision and exam prep.

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Reproduction in Organisms

LIFE perpetuates itself through REPRODUCTION — the biological process by which new individuals of the same species are produced. This chapter covers both ASEXUAL and SEXUAL reproduction across the plant and animal kingdoms. CBSE Class 12 Biology Chapter 1.

CBSE⏱ 18 minRead chapter

Human Reproduction

The HUMAN reproductive system is a masterpiece of biological engineering. This chapter explores the male and female reproductive systems, gametogenesis (spermatogenesis and oogenesis), the menstrual cycle, fertilisation, pregnancy, and parturition. CBSE Class 12 Biology Chapter 3.

CBSE⏱ 22 minRead chapter

Reproductive Health

REPRODUCTIVE HEALTH is about more than just the absence of disease — it is about PHYSICAL, MENTAL, and SOCIAL well-being in all aspects of reproductive function. CBSE Class 12 Biology Chapter 4.

CBSE⏱ 16 minRead chapter

Principles of Inheritance and Variation

Why do children RESEMBLE their parents? Why are they never EXACT copies? The answer lies in INHERITANCE — the transmission of genetic information from parents to offspring. This chapter covers Mendel's laws, linkage, mutations, and chromosomal disorders. CBSE Class 12 Biology Chapter 5.

CBSE⏱ 24 minRead chapter

Molecular Basis of Inheritance

HOW do genes work? What is DNA — and how does it STORE genetic information, REPLICATE, and DIRECT the synthesis of proteins? This is the MOLECULAR BASIS OF INHERITANCE — the central dogma of molecular biology. CBSE Class 12 Biology Chapter 6.

CBSE⏱ 24 minRead chapter

Evolution

EVOLUTION is the process by which species CHANGE over TIME. It is the UNIFYING THEORY of biology — explaining the diversity of life and the relationships between all living organisms. CBSE Class 12 Biology Chapter 7.

CBSE⏱ 20 minRead chapter

Human Health and Diseases

HEALTH is not just the absence of disease — it is a state of COMPLETE PHYSICAL, MENTAL, and SOCIAL well-being. This chapter covers common human diseases, the immune system, AIDS, cancer, and the effects of drugs and alcohol. CBSE Class 12 Biology Chapter 8.

CBSE⏱ 20 minRead chapter

Biotechnology — Principles and Processes

BIOTECHNOLOGY uses LIVING ORGANISMS or their components to CREATE useful products. The REVOLUTION began when scientists learned to MANIPULATE DNA at the molecular level. CBSE Class 12 Biology Chapter 9.

CBSE⏱ 18 minRead chapter

Biotechnology and Its Applications

Genetic engineering is not just a LABORATORY TOOL — it has REAL-WORLD applications in medicine, agriculture, and industry. This chapter explores the PRACTICAL IMPACT of biotechnology on human life. CBSE Class 12 Biology Chapter 10.

CBSE⏱ 16 minRead chapter

Organisms and Populations

ECOLOGY is the study of HOW organisms interact with each other and with their ENVIRONMENT. This chapter introduces the fundamental concepts of ecology — from the individual organism to the population. CBSE Class 12 Biology Chapter 11.

CBSE⏱ 16 minRead chapter

Ecosystem

An ECOSYSTEM is a FUNCTIONAL UNIT of nature — the LIVING community and the NON-LIVING environment WORKING TOGETHER as a system. This chapter explores ecosystem structure, function, energy flow, and nutrient cycling. CBSE Class 12 Biology Chapter 12.

CBSE⏱ 16 minRead chapter

Biodiversity and Conservation

BIODIVERSITY is the VARIETY of life on Earth — from genes to ecosystems. It is the FOUNDATION of the ecosystem services that sustain human civilisation, and it is under THREAT like never before. CBSE Class 12 Biology Chapter 13.

CBSE⏱ 16 minRead chapter