Last 5 Years CBSE Biology Question Papers |CBSE Biology Subject Marks Distribution

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CBSE Class 12th Biology Unit wise Weightage

Unit NumberTitleMarks
Unit VIReproduction14
Unit VIIGenetics and Evolution18
Unit VIIIBiology and Human Welfare14
Unit IXBiotechnology and its Applications10 
Unit XEcology and Environment14

Last 5 Year Question Paper of CBSE Class 12 Biology (Download Now )

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1.CBSE Class 12 Biology Question Paper 2019 Set 1Click Here
2.CBSE Class 12 Biology Question Paper 2019 Set 2Click Here
3.CBSE Class 12 Physics Question Paper 2019 Set 3Click Here
4.CBSE Class 12 Biology Question Paper 2019 Set 4Click Here
5.CBSE Class 12 Biology Question Paper 2019 Set 5Click Here
6.CBSE Class 12 Biology Question Paper 2018 Set 1Click Here
7.CBSE Class 12 Biology Question Paper 2017 Set 1Click Here
8.CBSE Class 12 Biology Question Paper 2017 Set 2Click Here
9.CBSE Class 12 Biology Question Paper 2016 Set 1Click Here
10.CBSE Class 12 Biology Question Paper 2016 Set 2Click Here
11.CBSE Class 12 Biology Question Paper 2013 Set 1Click Here

Biology CBSE Class 12th Syllabus

Unit-VI Reproduction

Chapter-1: Reproduction in Organisms

Reproduction, a characteristic feature of all organisms for continuation of species; modes of
reproduction,asexual and sexual reproduction; asexual reproduction – binary fission, sporulation, budding,gemmule formation, fragmentation; vegetative propagation in plants.

Chapter-2: Sexual Reproduction in Flowering Plants

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.

Chapter-3: Human Reproduction

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

Chapter-4: Reproductive Health

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).

Unit-VII Genetics and Evolution

Chapter-5: Principles of Inheritance and Variation

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.

Chapter-6: Molecular Basis of Inheritance

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

Chapter-7: Evolution

Origin of life; biological evolution and evidences for biological evolution (paleontology,
comparative anatomy, embryology and molecular evidences); Darwin’s contribution, modern
synthetic theory of evolution; mechanism of evolution – variation (mutation and recombination)
and natural selection with examples, types of natural selection; Gene flow and genetic drift;
Hardy – Weinberg’s principle; adaptive radiation; human evolution.

Unit-VIII Biology and Human Welfare

Chapter-8: Human Health and Diseases

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

Chapter-9: Strategies for Enhancement in Food Production

Animal husbandry, Plant breeding, tissue culture, single cell protein.

Chapter-10: Microbes in Human Welfare

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

Unit-IX Biotechnology and its Applications

Chapter-11: Biotechnology – Principles and Processes

Genetic Engineering (Recombinant DNA Technology).

Chapter-12: Biotechnology and its Application

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.

Unit-X Ecology and Environment

Chapter-13: Organisms and Populations

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.

Chapter-14: Ecosystem

Ecosystems: Patterns, components; productivity and decomposition; energy flow; pyramids of
number, biomass, energy; nutrient cycles (carbon and phosphorous); ecological succession;
ecological services – carbon fixation, pollination, seed dispersal, oxygen release (in brief).

Chapter-15: Biodiversity and its Conservation

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.

Chapter-16: Environmental Issues

Air pollution and its control; water pollution and its control; agrochemicals and their effects;
solid waste management; radioactive waste management; greenhouse effect and climate change
impact and mitigation; ozone layer depletion; deforestation; case study exemplifying success
story addressing environmental issue(s).