CBSE Sample Papers, Worksheets , Revision Notes

CBSE Class 12 Biology Chapter-wise Notes | Question Answers

Weightage of Content/Subject Units

Unit Content Marks
VI  Reproduction 14
VII  Genetics and Evolution 18
VIII  Biology and Human Welfare 14
IX  Biotechnology and its Applications 10
X  Ecology and Environment 14
Total 70

Weightage of Different Form of Questions

S.NO            Form of Questions   Marks for Each     No of Questions  Total Marks
1 Very Short Answer (VSA) 1 5 5
2 Short Answer ( SA I) 2 7 14
3 Short Answer ( SA II) 3 12 36
4 Long Answer ( LA ) 5 3 15
27 70

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.

CBSE Class 12 Biology Revision Notes Chapter 1 With Question Answers

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.

CBSE Class 12 Biology Revision Notes Chapter 2 With Question Answers

Chapter-3: Human Reproduction
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).

CBSE Class 12 Biology Revision Notes Chapter 3 With Question Answers

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).

CBSE Class 12 Biology Revision Notes Chapter 4 With Question Answers

Unit-VII Genetics and Evolution

Chapter-5: Principles of Inheritance and Variation
Heredity and variation: Mendelian inheritance; deviations from Mendelism – incomplete dominance, codominance, multiple alleles and inheritance of blood groups, pleiotropy; elementary idea of polygenic
inheritance; chromosome theory of inheritance; chromosomes and genes; Sex determination – in humans,
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.

CBSE Class 12 Biology Revision Notes Chapter 5 With Question Answers

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 and human and rice genome projects; DNA fingerprinting.

CBSE Class 12 Biology Revision Notes Chapter 6 With Question Answers

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.

CBSE Class 12 Biology Revision Notes Chapter 7 With Question Answers

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, ringworm) and their control; Basic concepts of
immunology – vaccines; cancer, HIV and AIDS; Adolescence – drug and alcohol abuse.

CBSE Class 12 Biology Revision Notes Chapter 8 With Question Answers

Chapter-9: Strategies for Enhancement in Food Production
Improvement in food production: Plant breeding, tissue culture, single cell protein,Biofortification,
Apiculture and Animal husbandry.

CBSE Class 12 Biology Revision Notes Chapter 9 With Question Answers

Chapter-10: Microbes in Human Welfare
In household food processing, industrial production, sewage treatment, energy generation and microbes as
biocontrol agents and biofertilizers. Antibiotics; production and judicious use.

CBSE Class 12 Biology Revision Notes Chapter 10 With Question Answers

Unit-IX Biotechnology and Its Applications

Chapter-11: Biotechnology – Principles and processes
Genetic Engineering (Recombinant DNA Technology).

CBSE Class 12 Biology Revision Notes Chapter 11 With Question Answers

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,
bio piracy and patents.

CBSE Class 12 Biology Revision Notes Chapter 12 With Question Answers

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

CBSE Class 12 Biology Revision Notes Chapter 13 With Question Answers

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).

CBSE Class 12 Biology Revision Notes Chapter 14 With Question Answers

Chapter-15: Biodiversity and its Conservation
Biodiversity-Concept, patterns, importance; loss of biodiversity; biodiversity conservation; hotspots,
endangered organisms, extinction, Red Data Book, biosphere reserves, national parks, sanctuaries and
Ramsar sites.

CBSE Class 12 Biology Revision Notes Chapter 15 With Question Answers

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; any one case study as success story addressing
environmental issue(s)

CBSE Class 12 Biology Revision Notes Chapter 16 With Question Answers