NCERT Solutions for Class 12 Biology helps students to learn concepts from CBSE syllabus easily. Moreover, the NCERT Solutions for Biology Class 12 is prepared by experienced faculty members and academic professionals. Hence, students have access to more resources than other similar websites. Moreover, we lay emphasis on understanding the conceptual basis of CBSE Biology subject, so that students can understand easily.
The topics covered in Class 12 NCERT Syllabus are of vital importance for competitive exams. So, we have compiled these solutions in such a way where students will be able to understand and memorize important topics easily.
NCERT Solutions for Class 12 Biology Chapter Wise
- 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
NCERT Solutions Class 12 Biology Chapter Details
Reproduction in Organisms
The chapter, Reproduction in Organisms, explains how different organisms are capable of producing. Reproduction is an important biological process in which an organism gives birth to its own offspring. There are two types of reproduction. When offspring are produced by a single parent with or without the involvement of gamete formation, 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 explained in detail with relevant diagrams and suitable examples.
Sexual Reproduction in Flowering Plants
Sexual Reproduction in Flowering Plants Explains the morphology, structure and processes of sexual reproduction in angiosperms. It also elaborates on sub-topics such as pre-fertilization: structure and events, double fertilization, post fertilization: structure and events, apomixis and polyembryony.
Human Reproduction
Reproductive events in humans include the formation of gametes (gametogenesis), i.e., sperm in males and ovum in females. Humans reach sexual maturity after attaining a certain age – this is called puberty. There are notable differences between reproductive events in males and females. In this chapter, you will examine the male and female reproductive systems in humans. The subtopics covered in this chapter are male reproductive system, female reproductive system, gametogenesis, menstrual cycle, fertilization and implantation, pregnancy and embryo development, childbirth and lactation.
Reproductive Health
In the previous chapter you learned about the human reproductive system and its functions. This chapter discusses closely related topic - reproductive health. The term refers only to healthy reproductive organs with normal functions. According to the World Health Organization , reproductive health means complete well-being in all aspects of reproduction, i.e. physical, emotional, behavioral and social. It includes sub-topics such as reproductive health-problems and strategies, population explosion and birth control, medical termination of pregnancy, sexually transmitted diseases, infertility.
Principles of Inheritance and Variation
Genetics is a branch of biology that deals with inheritance, as well as the variation of characters from parent to offspring. Inheritance is the process by which characters are transferred from parent to child; This is basis of heredity. Diversity is the degree to which offspring different from their parents. The chapter includes sub-topics such as Mendel's laws of inheritance, inheritance of one gene, inheritance of two genes, sex determination, mutation, genetic disorders.
Molecular Basis of Inheritance
In the previous chapter, you learned about the inheritance pattern and genetic basis of such models. At the time of Mendel, the nature of those 'factors' regulating the pattern of inheritance was not clear. Over the next hundred years, investigations into the nature of putative genetic material led to the realization that DNA – deoxyribonucleic acid – is the genetic material, at least for most organisms. You have learned in Class XI that nucleic acids are polymers of nucleotides. It also includes sub-topics such as DNA, The Search for Genetic Materials, RNA World, Replication, Transcription, Genetic Code, Translation, Regulation of Gene Expression, Human Genome Project and DNA Fingerprinting.
Evolution
It includes sub-topics such as Origin of life, Evolution of life forms - what is a theory, evidence of 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 students' study.
Human Health and Diseases
For a long time health was regarded as a state of body and mind where there was a balance of some humor. Health is affected by - (i) genetic disorders - defects with which the child is born and defects/defects which are inherited by the child from the parents from birth; (ii) transition and (iii) the lifestyle in which the food and water we take, the rest and exercise we give to our body, the habits that we have or are lacking, etc. The chapter also includes sub-topics such as Common Diseases in Humans, Immunity, AIDS, Cancer, Drugs and Alcohol Abuse.
Strategies for Enhancement in Food Production
With the ever-increasing population of the world, increasing food production is a major necessity. Many new technologies such as embryo transfer techniques and tissue culture techniques are going to play an important role in further increasing the food production. The sub-topics discussed in this chapter are animal husbandry, plant breeding, single cell protein and tissue culture.
Microbes in Human Welfare
Apart from macroscopic plants and animals, microorganisms are the major components of biological systems on this earth. You have studied about the diversity of organisms in class XI. Microorganisms are diverse – protozoa, bacteria, fungi and microscopic animal and plant viruses, viroids and prions also which are proteinaceous infectious agents. Microbes such as bacteria and many fungi can be grown on nutrient medium to form colonies that can be seen with the naked eye. Such cultures are useful in the study of micro-organisms. Some of the subtopics are microorganisms in household products, microorganisms in industrial products, microorganisms in sewage treatment, microorganisms in the production of biogas, microorganisms as biocontrol agents and microorganisms as biofertilizers.
Biotechnology Principles and Processes
Biotechnology is concerned with the technology of using living organisms or enzymes to produce products and processes useful to humans. The European Federation of Biotechnology (EFB) has given a definition of biotechnology that includes both traditional approaches and modern molecular biotechnology. The definition given by the EFB is as follows: 'the integration of the natural sciences and molecular analogues of organisms, cells, their parts and products and services'. Some of the topics mentioned in the chapter are principles of biotechnology, tools of recombinant DNA technology and processes of recombinant DNA technology.
Biotechnology: and its Application
Biotechnology, as you may have learned from the previous chapter, essentially deals with the industrial scale production of biopharmaceuticals and organics using genetically modified microbes, fungi, plants and animals. Applications of biotechnology include medical science, diagnostics, genetically modified crops for agriculture, processed food, bioremediation, waste treatment and energy production. The chapter also covers topics such as Biotechnology Applications in Agriculture, Biotechnology Applications in Medicine, Transgenic Animals and Ethical Issues.
Organisms and Populations
You have learned in earlier classes that ecology is a discipline that studies the interactions between organisms and between organisms and their physical (abiotic) environment. Ecology is basically concerned with the four levels of biological organization – organisms, populations, communities and biomes. In this chapter, we explore ecology at the organism and population levels. It also includes sub-topics like organism and its environment, population.
Ecosystem
An ecosystem can be viewed as a functional unit of nature, where living organisms interact with each other and also with the surrounding physical environment. In this chapter, we will first look at the structure of an ecosystem to appreciate inputs (productivity), transfer of energy (food chain/web, nutrient cycling) and outputs (erosion and energy loss). We will also look at the relationships – chakras, chains, webs – that form as a result of these energy flows and their interrelationship within the system. It includes sub-topics such as ecosystem-structure and function, productivity, decomposition, energy flow, ecological pyramid, ecological succession, nutrient cycle and ecosystem services.
Biodiversity and Conservation
Biodiversity and conservation includes topics such as genetic diversity, species diversity, ecological diversity, different types of species, patterns of diversity, loss of biodiversity, biodiversity conservation, etc. Biodiversity conservation can take place in situ as well as ex situ. In situ conservation, endangered species are preserved in their natural habitat in order to protect the entire ecosystem. Out-of-space conservation methods include the protective maintenance of threatened species in zoological parks and botanical gardens, in vitro fertilization, tissue culture propagation, and cryopreservation of gametes.
Environmental Issues
The size of the human population has increased tremendously in the last hundred years. This means an increase in the demand for food, water, homes, electricity, roads, automobiles and many other commodities. Pollution is any undesirable change in the physical, chemical or biological characteristics of air, land, water or soil. The factors causing such unwanted changes are called pollutants. Other sub-topics that students will study in this chapter are air pollution and its control, water pollution and its control, solid waste, agrochemicals and their effects, radioactive waste, greenhouse effect and global warming, ozone depletion in the stratosphere Scarcity, degradation and maintenance by improper resource use, deforestation.
Many important concepts like reproduction, inheritance, evolution, food production, biotechnology, ecosystem, biodiversity are explained in depth.
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