NCERT Solutions for Class 12 Biology (Updated for 2021

Download Chapter wise NCERT Solutions For Class 12 Biology

NCERT Solutions for Class 12 Biology helps students to learn concepts from the CBSE syllabus easily. Furthermore, Biology NCERT Solutions Class 12 is prepared by experienced faculty members and the academic professionals. Therefore, students have access to more resources than other similar websites. Moreover, we emphasise on understanding the conceptual basis of CBSE Biology subject, so that students can comprehend with ease.

The topics covered in the Class 12 NCERT syllabus carry a significant weightage for the competitive exams. Hence, we have compiled these solutions in a manner where students will be able to understand and recall the important topics with ease.

NCERT Solutions for Class 12 Biology Chapter Wise

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NCERT Solutions Class 12 Biology Chapter Details and Exercises

Chapter 1: Reproduction in Organisms

The chapter, Reproduction in Organisms, explains how various organisms are able to procreate. Reproduction is an important biological process in which an organism gives rise to young ones similar to itself. There are two types of reproduction. When offspring is produced by a single parent with or without the involvement of gamete formation, the reproduction is asexual. When two parents (opposite sex) participate in the reproductive process and also involve the fusion of male and female gametes, it is called sexual reproduction. These concepts are elaborately explained with relevant diagrams and suitable examples.

Also access the following resources for Class 12 Chapter 1 Reproduction in Organisms at BYJU’S:

Chapter 2: Sexual Reproduction in Flowering Plants – Term I

Sexual Reproduction in Flowering Plants explains the morphology, structure and the processes of sexual reproduction in angiosperms. It also elaborates on subtopics such as pre-fertilisation: Structure and Events, Double fertilisation, Post fertilisation: Structure and Events, Apomixis and Polyembryony.

Topics Covered in Class 12 CBSE Biology Chapter 2 Sexual Reproduction in Flowering Plants for First Term:

Flower structure; development of male and female gametophytes; pollination – types, agencies and examples; outbreeding devices; pollen-pistil interaction; double fertilization; post fertilization events – development of endosperm and embryo, development of seed and formation of fruit; special modes- apomixis, parthenocarpy, polyembryony; Significance of seed dispersal and fruit formation.

Also access the following resources for Class 12 Chapter 2 Sexual Reproduction in Flowering Plants at BYJU’S:

Chapter 3: Human Reproduction – Term I

Reproductive events in humans include the formation of gametes (gametogenesis), i.e., sperms in males and ovum in females. Humans reach sexual maturity after attaining a certain age – this is called puberty. There are remarkable differences between the reproductive events in the male and in the female. In this chapter, you will examine the male and female reproductive systems in humans. The subtopics covered in this chapter are the male reproductive system, the female reproductive system, gametogenesis, menstrual cycle, fertilisation and implantation, pregnancy and embryonic development, parturition and lactation.

Topics Covered in Class 12 CBSE Biology Chapter 3 Human Reproduction for First Term:

Male and female reproductive systems; microscopic anatomy of testis and ovary; gametogenesis – spermatogenesis and oogenesis; menstrual cycle; fertilisation, embryo development upto blastocyst formation, implantation; pregnancy and placenta formation (elementary idea); parturition (elementary idea); lactation (elementary idea).

Also access the following resources for Class 12 Chapter 3 Human Reproduction at BYJU’S:

Chapter 4: Reproductive Health – Term I

In the previous chapter, you have learnt about the human reproductive system and its functions. This chapter discusses a closely related topic – reproductive health. The term simply refers to healthy reproductive organs with normal functions. According to the World Health Organisation (WHO), reproductive health means total well-being in all the aspects of reproduction, i.e., physical, emotional, behavioural and social. It covers subtopics such as Reproductive health –Problems and Strategies, Population Explosion and Birth Control, Medical Termination of Pregnancy, Sexually Transmitted Diseases, Infertility.

Topics Covered in Class 12 CBSE Biology Chapter 4 Reproductive Health for First Term:

Need for reproductive health and prevention of Sexually Transmitted Diseases (STDs); birth control – need and methods, contraception and medical termination of pregnancy (MTP); amniocentesis; infertility and assisted reproductive technologies – IVF, ZIFT, GIFT (elementary idea for general awareness).

Also access the following resources for Class 12 Chapter 4 Reproductive Health at BYJU’S:

Chapter 5: Principles of Inheritance and Variation – Term I

Genetics is a branch of Biology that deals with inheritance, as well as the variation of characters from parents to offspring. Inheritance is the process by which the characters are passed on from parent to progeny; it is the basis of heredity. Variation is the degree by which progeny differ from their parents. The chapter covers subtopics such as Mendel’s Laws of Inheritance, Inheritance of One Gene, Inheritance of Two Genes, Sex Determination, Mutation, Genetic Disorders.

Topics Covered in Class 12 CBSE Biology Chapter 5 Principles of Inheritance and Variation for First Term:

Heredity and variation: Mendelian inheritance; deviations from Mendelism – incomplete dominance, co-dominance, multiple alleles and inheritance of blood groups, pleiotropy; elementary idea of polygenic inheritance; chromosome theory of inheritance; chromosomes and genes; Sex determination – in human being, birds and honey bee; linkage and crossing over; sex linked inheritance – haemophilia, colour blindness; Mendelian disorders in humans -thalassemia; chromosomal disorders in humans; Down’s syndrome, Turner’s and Klinefelter’s syndromes.

Also access the following resources for Class 12 Chapter 5 Principles of Inheritance and Variation at BYJU’S:

Chapter 6: Molecular Basis of Inheritance – Term I

In the previous chapter, you have learnt the inheritance patterns and the genetic basis of such patterns. At the time of Mendel, the nature of those ‘factors’ regulating the pattern of inheritance was not clear. Over the next hundred years, the nature of the putative genetic material was investigated culminating in the realisation that DNA – deoxyribonucleic acid – is the genetic material, at least for the majority of organisms. In Class XI you have learnt that nucleic acids are polymers of nucleotides. It also includes subtopics such as The DNA, The Search for Genetic Material, RNA World, Replication, Transcription, Genetic Code, Translation, Regulation of Gene Expression, Human Genome Project and DNA Fingerprinting.

Topics Covered in Class 12 CBSE Biology Chapter 6 Molecular Basis of Inheritance for First Term:

Search for genetic material and DNA as genetic material; Structure of DNA and RNA; DNA packaging; DNA replication; Central Dogma; transcription, genetic code, translation; gene expression and regulation – lac operon; Genome, Human and rice genome projects; DNA fingerprinting.

Also access the following resources for Class 12 Chapter 6 Molecular Basis of Inheritance at BYJU’S:

Chapter 7: Evolution

Evolutionary Biology is the study of history of life forms on earth. It covers subtopics such as Origin of Life, Evolution of Life Forms – A Theory, What are the Evidences for Evolution? What is Adaptive Radiation? Biological Evolution, Mechanism of Evolution, Hardy – Weinberg Principle, A Brief Account of Evolution, Origin and Evolution of Man related to Evolution, which is important for the students to study.

Also access the following resources for Class 12 Chapter 7 Evolution at BYJU’S:

Chapter 8: Human Health and Diseases – Term II

Health, for a long time, was considered as a state of body and mind where there was a balance of certain humor. Health is affected by – (i) genetic disorders – deficiencies with which a child is born and deficiencies/defects which the child inherits from parents from birth; (ii) infections and (iii) lifestyle including food and water we take, rest and exercise we give to our bodies, habits that we have or lack, etc. The chapter also includes subtopics such as Common Diseases in Humans, Immunity, AIDS, Cancer, Drugs and Alcohol Abuse.

Topics Covered in Class 12 CBSE Biology Chapter 8 Human Health and Diseases for Second Term:

Pathogens; parasites causing human diseases (malaria, dengue, chikungunya, filariasis, ascariasis, typhoid, pneumonia, common cold, amoebiasis, ring worm) and their control; Basic concepts of immunology – vaccines; cancer, HIV and AIDS; Adolescence – drug and alcohol abuse.

Also access the following resources for Class 12 Chapter 8 Human Health and Diseases at BYJU’S:

Chapter 9: Strategies for Enhancement in Food Production

With ever-increasing population of the world, enhancement of food production is a major necessity. Biological principles, as applied to animal husbandry and plant breeding have a major role in our efforts to increase food production. Several new techniques like embryo transfer technology and tissue culture techniques are going to play a pivotal role in further enhancing food production. Subtopics that are explained in this chapter are Animal Husbandry, Plant Breeding, Single Cell Proteins and Tissue Culture.

Also access the following resources for Class 12 Chapter 9 Strategies for Enhancement in Food Production at BYJU’S:

Chapter 10: Microbes in Human Welfare – Term II

Besides macroscopic plants and animals, microbes are the major components of biological systems on this earth. You have studied about the diversity of living organisms in Class XI. Microbes are diverse–protozoa, bacteria, fungi and microscopic animal and plant viruses, viroids and also prions that are proteinaceous infectious agents. Microbes like bacteria and many fungi can be grown on nutritive media to form colonies that can be seen with the naked eyes. Such cultures are useful in studies on micro-organisms. Few of the subtopics are Microbes in Household Products, Microbes in Industrial Products, Microbes in Sewage Treatment, Microbes in Production of Biogas, Microbes as Biocontrol Agents and Microbes as Biofertilisers.

Topics Covered in Class 12 CBSE Biology Chapter 10 Microbes in Human Welfare for Second Term:

Microbes in food processing, industrial production, sewage treatment, energy generation and microbes as bio-control agents and bio-fertilizers. Antibiotics; production and judicious use.

Also access the following resources for Class 12 Chapter 10 Microbes in Human Welfare at BYJU’S:

Chapter 11: Biotechnology Principles and Processes – Term II

Biotechnology deals with technique of using live organisms or enzymes from organisms to produce products and processes useful to humans. The European Federation of Biotechnology (EFB) has given a definition of biotechnology that encompasses both traditional view and modern molecular biotechnology. The definition given by EFB is as follows: ‘The integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services’. Some of the subtopics mentioned in the chapter are Principles of Biotechnology, Tools of Recombinant DNA Technology and Processes of Recombinant DNA Technology.

Topics Covered in Class 12 CBSE Biology Chapter 11 Biotechnology Principles and Processes for Second Term:

Genetic Engineering (Recombinant DNA Technology).

Also access the following resources for Class 12 Chapter 11 Biotechnology Principles and Processes at BYJU’S:

Chapter 12: Biotechnology: and its Application – Term II

Biotechnology, as you would have learnt from the previous chapter, essentially deals with the industrial-scale production of biopharmaceuticals and biologicals using genetically modified microbes, fungi, plants and animals. The applications of biotechnology include therapeutics, diagnostics, genetically modified crops for agriculture, processed food, bioremediation, waste treatment and energy production. The chapter also includes topics such as Biotechnological Applications in Agriculture, Biotechnological Applications in Medicine, Transgenic Animals and Ethical Issues.

Topics Covered in Class 12 CBSE Biology Chapter 12 Biotechnology: and its Application for Second Term:

Application of biotechnology in health and agriculture: Human insulin and vaccine production, stem cell technology, gene therapy; genetically modified organisms – Bt crops; transgenic animals; biosafety issues, biopiracy and patents.

Also access the following resources for Class 12 Chapter 12 Biotechnology: and its Application at BYJU’S:

Chapter 13: Organisms and Populations – Term II

You have already learnt in the previous classes that Ecology is a subject which studies the interactions among organisms and between the organism and its physical (abiotic) environment. Ecology is basically concerned with four levels of biological organisation – organisms, populations, communities and biomes. In this chapter, we explore ecology at organismic and population levels. It also includes subtopics such as Organism and Its Environment, Populations.

Topics Covered in Class 12 CBSE Biology Chapter 13 Organisms and Populations for Second Term:

Organisms and environment: Habitat and niche, population and ecological adaptations; population interactions – mutualism, competition, predation, parasitism; population attributes – growth, birth rate and death rate, age distribution.

Also access the following resources for Class 12 Chapter 13 Organisms and Populations at BYJU’S:

Chapter 14: Ecosystem

An ecosystem can be visualised as a functional unit of nature, where living organisms interact among themselves and also with the surrounding physical environment. In this chapter, we will first look at the structure of the ecosystem, in order to appreciate the input (productivity), transfer of energy (food chain/web, nutrient cycling) and the output (degradation and energy loss). We will also look at the relationships – cycles, chains, webs – that are created as a result of these energy flows within the system and their inter- relationship. It includes subtopics such as Ecosystem–Structure and Function, Productivity, Decomposition, Energy Flow, Ecological Pyramids, Ecological Succession, Nutrient Cycling and Ecosystem Services.

Also access the following resources for Class 12 Chapter 14 Ecosystem at BYJU’S:

Chapter 15: Biodiversity and Conservation – Term II

Biodiversity and Conservations consist of topics like Genetic diversity, Species diversity, Ecological diversity, Different types of Species, Patterns of Diversity, Loss of Biodiversity, Biodiversity Conservation, etc. Biodiversity conservation may be in situ as well as ex situ. In in situ conservation, the endangered species are protected in their natural habitat so that the entire ecosystem is protected. Ex situ conservation methods include protective maintenance of threatened species in zoological parks and botanical gardens, in vitro fertilisation, tissue culture propagation and cryopreservation of gametes.

Topics Covered in Class 12 CBSE Biology Chapter 15 Biodiversity and Conservation for Second Term:

Biodiversity – Concept, patterns, importance; loss of biodiversity; biodiversity conservation; hotspots, endangered organisms, extinction, Red Data Book, Sacred Groves, biosphere reserves, national parks, wildlife, sanctuaries and Ramsar sites.

Also access the following resources for Class 12 Chapter 15 Biodiversity and Conservation at BYJU’S:

Chapter 16: Environmental Issues

Human population size has grown enormously over the last hundred years. This means the increase in demand for food, water, home, electricity, roads, automobiles and numerous other commodities. Pollution is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil. The agents that bring about such an undesirable change are called pollutants. The other subtopics students will study in this chapter are Air Pollution and Its Control, Water Pollution and Its Control, Solid Wastes, Agrochemicals and their Effects, Radioactive Wastes, Greenhouse Effect and Global Warming, Ozone Depletion in the Stratosphere, Degradation by Improper Resource Utilisation and Maintenance, Deforestation.

Several important concepts, such as reproduction, inheritance, evolution, food production, biotechnology, ecosystem, biodiversity, are explained in-depth. The concepts have also been updated as per the latest syllabus prescribed by the CBSE board.

Also access the following resources for Class 12 Chapter 16 Environmental Issues at BYJU’S:

BYJU’S is a learning company and we thoroughly understand the importance of study materials and their implications on the academic excellence. Hence, we have designed Class 12 NCERT Solutions, a learning resource aimed to help students study and achieve results.

CBSE Marking Scheme 2021-22

Students will be facing the board exams twice in their lifetime. One is the Class 10 and the other one is Class 12. The score obtained in Class 10 help students understand to understand the subject which they are strong at and the marks scored in Class 12 help students plan their future. Keeping this in mind, the CBSE board has equally divided the entire syllabus into two terms to help students learn all the concepts easily. Going through the course structure updated by the CBSE board, students will be able to understand the chapters which are of more marks and work on them accordingly.

Term I and II CBSE Class 12 Biology Syllabus Course Structure 2021-22

Units	Term – I	Marks
VI	Reproduction: Chapter – 2, 3 and 4	15
VII	Genetics and Evolution: Chapter – 5 and 6	20
Units	Term – II	Marks
VIII	Biology and Human Welfare: Chapter – 8 and 10	14
IX	Biotechnology and its Applications: Chapter – 11 and 12	11
X	Ecology and Environment: Chapter – 13 and 15	10
	Total Theory (Term – I and Term – II)	70
	Practicals Term – I	15
	Practicals Term – II	15
	Total	100

Class 12 Biology NCERT Solutions

Biology NCERT Solutions for Class 12 is more effective than any other educational resource. We provide elaborate explanations, detailed solutions, descriptive diagrams and more. Further, we provide accurate and updated answers to all the exercise questions given in NCERT textbooks.

Downloadable files of eBooks, notes, PDFs are also available to let students study at their convenience.

Benefits of Biology NCERT Solutions Class 12

Researched and written by experienced teachers
New Value-Based Questions with solutions in each chapter
Jargon-free, easy language
Content formulated as per CBSE curriculum
Extensive coverage of fundamental concepts
The best resource for CBSE board exam preparation

Detailed Analysis of NCERT Solutions Class 12 Biology

NCERT Textbooks are well known for their simplicity and straightforward description of concepts. These textbooks are ideal for students of CBSE Class 12. It comprises questions that test their conceptual understanding.

The Biology NCERT Solutions Class 12 features all the necessary information with basic concepts to help the students in the preparation of medical entrance exams like NEET.

Important Topics under NCERT Solutions Class 12 Biology

Principles of Inheritance and Variations
Reproduction in organisms
Microbes in Human Welfare
Evolution
Biotechnology

Class 12 NCERT Biology Solutions Practice Questions

Q1. What is the asexual reproductive structure in Sponge?

Q2. True or false: Independent assortment can be seen in a monohybrid cross.

Q3. Write one difference each between Oestrus cycle and Menstrual cycle

Q4. Elaborate the following:

Apomixis
Scutellum

Q5. How are microspores in angiosperms developed?

Q6. Name the hormones produced by women during pregnancy?

Q7. Write one difference between codominance and incomplete dominance.

Q8. Who rediscovered Mendel’s laws?

Q9. YyRr is crossed with wrinkled pea plant. Explain the result with the diagram.

Q10. Define mutagen. Give one example.

Q11. Define MTP.

Q12. What is menarche?

Q13. Draw a labelled diagram of the seminiferous tubule.

Q14. Which part of the fallopian tube is closest to the ovary?

Q15. Draw anatropous ovule and label any six parts.

Q16. What happens to Synergids after fertilization?

Q17. What is the significant difference between autogamy, xenogamy, and geitonogamy?

Q18. What are the gamete mother cells called in diploid organisms?

Q19. Explain the process of cross-pollination in plants.

Discover more questions, concepts and topics in CBSE Biology at BYJU’S. Alternatively, explore NCERT solutions for Maths, Physics, and Chemistry by registering at BYJU’S.

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Frequently Asked Questions on NCERT Solutions for Class 12 Biology

How NCERT Solutions of Class 12 Biology helps in exam preparation?

The questions provided in NCERT textbooks can offer an excellent boost to study thoroughly and score excellently during examinations and tests. Students can effectively start practicing NCERT Solutions Class 12 Biology, which will happen in more immeasurable performance in further studies. This, in turn, would build a strong grip in the syllabus.

Which book is best for Class 12 Biology?

The most esteemed book for the Class 12 exam is NCERT Biology Textbook. These books strictly follow the CBSE curriculum. It helps to form the base for preparing for the board examinations as it contains question papers that are set according to the prescribed CBSE syllabus of the subject.

How to download NCERT Solutions for Class 12 Biology?

Visit BYJU’S website and select NCERT Solutions, or go to the link https://byjus.com/ncert-solutions/, select the class 12/select subject and view/download the solutions. These solutions provided by BYJU’S cover all these concepts, with detailed explanations.

Does BYJU’S website provide free NCERT Biology Solutions for Class 12?

Yes, these solutions can be viewed and downloaded in free PDF format. Students who find it difficult in solving exercise wise questions of NCERT textbook can access PDF solutions. The questions are solved by our experts in the best possible way to make it easier for the students during exam preparation.

What is the structure responsible for asexual reproduction in sponges?

Gemmules are the structure responsible for asexual reproduction in sponges.

Explain the law of independent assortment.

The law of independent assortment states that the alleles of two or more different genes get sorted into gametes independent of one another.

What is apomixis?

Apoximis is a form of asexual reproduction that occurs without fertilization and does not involve meiosis. This form of reproduction is more common in plants.

NCERT Solutions For Class 12 Biology