CBSE Class 12th Biology Syllabus 2023

Unit VI: Reproduction

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 fertilisation; post

fertilisation events - development of endosperms and embryos, development of seeds, 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 ovaries; gametogenesis

-spermatogenesis and oogenesis; menstrual cycle; fertilisation; embryo development up to

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 - needs and methods, contraception and medical termination of pregnancy (MTP);

amniocentesis; infertility and assisted reproductive technologies - IVF, ZIFT, GIFT (elementary

ideas 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 humans, birds and honey bees; linkage and crossover; 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

fingerprinting. 

Chapter-7: Evolution

Origin of life: biological evolution and evidence of biological evolution (palaeontology,

comparative anatomy, embryology and molecular evidence); Darwin's contribution, modern

synthetic theory of evolution; mechanism of evolution - variation (mutation and recombination)

and natural selection with examples and types of natural selections; 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

abuse.

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 Applications
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
Population interactions - mutualism, competition, predation, parasitism; population attributes -

growth, birth rate, death rate, and age distribution. (Topics excluded: Organism and its

Environment, Major Aboitic Factors, Responses to Abiotic Factors, Adaptations)

Chapter-14: Ecosystem
Ecosystems: Patterns, components; productivity and decomposition; energy flow; pyramids of

Number, Biomass, Energy (Topics excluded: Ecological Succession and Nutrient Cycles)

Chapter-15: Biodiversity and its Conservation
Biodiversity-Concepts, 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.

Experiments

• Prepare a temporary mount to observe pollen germination.

• Study plant population density using the quadrat method.

• Study plant population frequency using the quadrat method.

• Prepare a temporary mount of onion root tips to study mitosis.

• Isolate DNA from available plant materials such as spinach, green pea seeds, papaya, etc.

Spotting

• Flowers adapted to pollination by different agencies (wind, insects, birds).

• Pollen germination of stigma through a permanent slide or scanning electron micrograph.

• Identify the stages of gamete development, i.e., T.S. of testis and T.S. of ovaries through permanent slides (from grasshopper/mice).

• Meiosis in onion bud cell or grasshopper testis through permanent slides.

• T.S. of the blastula through permanent slides (Mammalian).

• Mendelian inheritance using seeds of different colors/sizes of any plant.

• Prepared pedigree charts of any one of the genetic traits such as rolling of tongue, blood

• groups, ear lobes, widow's peak and colour blindness.

• Controlled pollination - emasculation, tagging and bagging.

• Common diseases, organisms like Ascaris, Entamoeba, Plasmodium, any fungus

• causing ringworms through permanent slides, models, virtual images, or specimens.

• Comment on symptoms of diseases that they cause

• Model specimen showing symbolic association in root modules of leguminous plants,

  Cuscuta on host, lichens.

• Flash card models showing examples of homologous and analogous organs.

Experiments/Identification

• Beakers, flask, Petri plates, soil from different sites - sandy, clayey, loamy,

  small potted plants, aluminium foil, paintbrush, test tubes, starch solution, iodine, ice cubes,

  Bunsen burner/spirit lamp/water bath, large flowers, Maize inflorescence, model of

  developmental stages highlighting the morula and blastula of frogs, beads/seeds of different

  shapes/size/texture Ascaris, Cactus/Opuntia(model).

Practicals

• Study of flowers adapted to pollination by different agencies (wind, insects).

• Identification of T.S of morula or blastula of frog (Model).

• Study of Mendelian inheritance patterns using beads/seeds of different sizes/textures.

• Prepare pedigree charts of genetic traits such as rolling of the tongue and color blindness.

• Study emasculation, tagging, and bagging by trying out an exercise on

  controlled pollination.

• Identify common disease-causing organisms like Ascaris (model) and learn some

  common symptoms of the disease that they cause.

• Comment upon morphological adaptations of plants found in xerophytic conditions.

VI

Reproduction

16

VII

Genetics and Evolution

20

VIII

Biology and Human Welfare

12

IX

Biotechnology and its Applications

12

X

Ecology and Environment

10

Total

70

One Major Experiment

5

One Minor Experiment

4

Slide Preparation

5

Spotting 

7

Practical Record + Viva Voce

4

Investigatory Project and its

Project Record + Viva Voce

5

Total 

30

Identification/Familiarity with the apparatus 

5

Written test (Based on given/prescribed practicals) 

10

Viva 

10

Practical Records 

5

Total 

30