Biology Science (English Medium) Class 12 CBSE Syllabus 2025-26

• Flower
• Significance of flower

• Sexual Reproduction in Flowering Plants
• Stages of Sexual Reproduction in Flowering Plants
  (i) Pre-fertilisation events
  (ii) Double fertilisation
  (iii) Post-fertilisation events

• Abiotic Agents
• Biotic Agents

• Double Fertilization 
• Significance of Double Fertilization 
• Syngamy and Triple Fusion

• Embryogenesis
• Development of Dicot Embryo as in Capsella
• Development of Monocot (grass) Embryo 

• Apomixis
• Classification of apomixis

1. Recurrent apomixis
2. Non-recurrent apomixis
3. Adventive apomixis

• Definition of Life Span
• Characteristics of the life span of Organisms
• Life span development

• Maximum life span of organisms
• Approximate life spans of some organisms

• Definition and Meaning of Reproduction: 
• Purpose of Reproduction
• Basic Features of Reproduction: 
• Factors Responsible for Reproduction

• Asexual reproduction in plant

• Different modes of asexual reproduction in plant

1. Fragmentation
2. Budding
3. Spore formation
4. Binary fission
5. Conidia formation
6. Gemma formation

• Different Phases in Sexual Reproduction in Plant
• Different Phases in Sexual Reproduction in animals

• Gametogenesis

1. Spermatogenesis
2. Structure of human spermatozoan
3. Oogenesis
4. Structure of ovum

• Menstrual Cycle (Ovarian Cycle)
• Phases menstrual cycle

1. Menstrual phase
2. Follicular or proliferative phase
3. Ovulatory phase
4. Luteal or secretory phase

• Menstrual disorders
• Menstrual hygiene
• Disposal of Napkins

• Gastrulation
• Extra embryonic membranes
• Placenta
• Changes in embryo during pregnancy

• Reproductive and Child Health Care (RCH) Programme
  - Goals of RCH Programmes

• Population Explosion
• Reasons for population explosion
• Impact of population explosion
• Methods to control population explosion

• Population stabilisation and birth control
• Contraceptive methods

1. Temporary method:
   a. Natural method/ Safe period / Rhythm method
   b. Coitus Interruptus or withdrawal
   c. Lactational amenorrhea (absence of menstruation)
   d. Chemical means (spermicides)
   e. Mechanical means / Barrier methods
   f. Physiological (Oral) Devices
2. Permanent Methods

• Introduction
• Some Sexually Transmitted Diseases
• Other diseases of the Reproductive Tract

• IVF-ET: in vitro fertilization and embryo transfer. 
• ICSI: Intracytoplasmic Sperm Injection  
• GIFT: Gamete Intrafallopian Transfer 
• ZIFT: Zygote Intrafallopian Transfer  
• IUT: Intra-Uterine Transfer
• IUI: Intra-Uterine insemination
• Adoption

• Mendelism
• Father of Genetics - Gregor Johann Mendel
• Reasons for Mendel's success
• Advantages of selecting pea plant for experiment by Mendel

• Monohybrid Cross
• Representation of a Gene

• Back cross 
• Test cross 

• Mendel’s Principles of Heredity
• Mendelian inheritance - Mendel’s Laws of Heredity

 Sex Determination

1. Sex Determination in human beings 
2. Sex Determination in birds 
3. Sex Determination in honey bees  

• Types of mutation
• Mutagenic agents
• Chromosomal mutations

• Genetic Disorders
• Examples of Genetic Disorders

• Linkage
• Types of linkage: Complete linkage and Incomplete linkage
• Linkage Groups
• Sex-linkage: Complete sex linkage and Incomplete sex linkage
• Crossing Over
• Morgan’s Experiments showing linkage and crossing over

• The Discovery of DNA
• Introduction of DNA
• Composition of DNA
• Genes: The Functional Units of Heredity
• Seeds of Technology

• Packaging in Prokaryotes
• Packaging in Eukaryotes

• Functions of DNA:

1. Heterocatalytic function
2. Autocatalytic function

Process of semicoservative replication 

• Activation of Nucleotides 
• Point of Origin or Initiation point 
• Unwinding of DNA molecule 
• Replicating fork 
• Synthesis of new strands 
• Leading and Lagging strand 
• Formation of daughter DNA molecules

• Protein synthesis
• Process of protein synthesis: Transcription and Translation
• Central Dogma

• Characteristics of Genetic code 
• Mutations and Genetic Code 

• Mechanism of Translation

• Operon
• Lactose or lac operon
• Lac operon consists of the following components:

1. Regulator gene (repressor gene) 
2. Promoter gene
3. Operator gene
4. Structural genes
5. Inducer

• Role of lactose

• Human Genome Project
• Goals of HGP
• Methodologies
• Salient Features of Human Genome
• Applications and Future Challenges

• DNA Fingerprinting Technique
• Steps involved in DNA finger printing
• Application of DNA fingerprinting

• Origin of life
• Theories of origin of life

1. Big Bang Theory
2. Theory of Panspermia
3. Theory of Spontaneous Generation or Abiogenesis
4. Theory of Biogenesis
5. Theory of Chemical Origin
6. Urey and Miller's experiment

• Evidence for Biological evolution:

1. Paleontological evidence
2. Evidence from Morphological and anatomical evidence
3. Embryological evidence
4. Molecular evidence
5. Evolution by natural selection (Industrial melanism)
6. Evolution by anthropogenic

• Speciation
• Modes to form New species

1. Intraspecific Speciation: Allopatric speciation and Sympatric speciation
2. Interspecific Speciation: Hybridisation

• Types of Immunity

1. Innate immunity or Inborn immunity

1. Epithelial surface
2. Antimicrobial substances in blood and
   tissues
3. Cellular factors in innate immunity
4. Fever
5. Acute phase proteins (APPs)

2. Acquired immunity

1. Active immunity

1. Natural Acquired Active immunity
2. Artificial Acquired Active immunity

      II. Passive immunity

1. Natural Acquired Passive immunity
2. Artificially Acquired Passive
   immunity

• Vaccination
• Immunization

• Lymphoid organs:

1. Primary or central lymphoid organs: Thymus gland, Bone marrow
2. Secondary lymphoid organs: Lymph node, Spleen, Peyer’s patches, Tonsils, Spleen, Adenoids, MALT, GALT, BALT.

• Introduction
• Some Sexually Transmitted Diseases
• Other diseases of the Reproductive Tract

• Introduction of Cancer
• Differences between normal cell and cancer cell
• Causes of cancer
• Cancer detection and diagnosis
• Treatment of cancer
• Scope of Immunology

• Agro-Complementary Occupations
• Animal Husbandry

• Proper Care for Optimal Yield
• Dairy Farm Management
• Protecting the Cattle from Diseases
• Livestock Management: Sheep, Goats, and Horses

• Poultry Farm Management
• Components of Poultry Farm Management
• Egg and Broiler Production
• Poultry Disease

Plant breeding

• Hybridization and its technique
  Steps of Hybridization technique
  Indian Hybrid Crops 
• Mutation Breeding

         -Plant Breeding for Developing a Resistance to Insect Pest

• Single cell protein (SCP)
• Advantages of Single-Cell Protein

• Definition
• Introduction
• Tissue Culture Stages
• Processes in Tissue Culture

• Microbes in Household Food Processing
• Curd, Idli, Bread, Traditional drinks and food, Cheese
• Single cell protein (SCP)

Microbes in Industrial Production

1. Production of Alcoholic Beverages 
2. Production of organic acids 
3. Production of vitamins 
4. Production of Antibiotics 
5. Production of Enzymes 
6. Gibberellin production 

Composition of Sewage

Microorganisms in Sewage

Sewage treatment process includes four basic steps as follows:

1. Preliminary Treatment
2. Primary treatment (physical treatment)
3. Secondary treatment (biological treatment)
4. Tertiary treatment

• methanogens, biogas plant

• Microbes as Biocontrol Agents
• Examples of Microbial bio-control

• Biofertilizers
• Types of Biofertilizers
• Biofertilizer microorganisms
• Sources of Biofertilizers 
  a) Bacteria as a nitrogen fixer
  b) Fungi
  c) Cyanobacteria

Microbes in human welfare

• Microbes in food preparation

1. Dosa, Dhokla and Idli
2. Microbes as the Source of Food
3. Dairy Products

• Process and Principles of Biotechnology
• Technique of gene cloning and rDNA technology 

• Isolation of the Genetic Material (DNA)
• Cutting of DNA at Specific Locations
• Amplification of Gene of Interest using PCR
• Insertion of Recombinant DNA into the Host Cell/Organism
• Obtaining the Foreign Gene Product
• Downstream Processing

• In agriculture: for production of crops tolerant to abiotic stresses (cold, drought, salt, heat); pest-resistant crops (Bt-crops, RNAi with reference to Meloidogyne incognita); biofortification (golden rice, wheat – Atlas 66, maize hybrids, iron fortified rice)
• Genetically Modified Organisms - BT Crops

• In medicine: Genetically Engineered Insulin, Gene therapy - with reference to the treatment of SCID, molecular diagnosis by PCR, ELISA and use of DNA/RNA probe.

• Transgenic animals for bioactive products like alpha-1-antitrypsin for emphysema, alpha-lactalbumin

1. Normal physiology and development
2. Study of disease
3. Biological products
4. Vaccine safety
5. Chemical safety testing

• Bio Piracy and Patents
• GEAC (Genetic Engineering Approval Committee)
• Biopiracy
• Patents
• Cyber Crime
• Software Piracy
• Hacking
• Cracking

• Vaccine safety testing
• Chemical safety testing
• Study of disease

1. Healthcare Biotechnology 
2. Agriculture 
3. Gene therapy 
4. Genetically Modified Organisms (GMOs) 

• Case studies of waste water treatment (FOAM and EcoSan)

• Municipal solid wastes
  ⇒ Steps that can be taken by us to reduce the non-biodegradable waste
  (i) Burning of the waste
  (ii) Sanitary landfills
• Hospital Waste
• Electronic waste (e-waste)
• Incineration
• Recycling
• Case Study of Remedy for Plastic Waste

• Agrochemicals
• Effects of Agrochemicals
• Biomagnification
• Eutrophication
• Case Study of Organic Farming

• Greenhouse effect
• Global warming
• Effects of global warming
• Prevention of global warming

• Soil erosion and desertification
• Waterlogging and soil salinity

• Deforestation
• Causes of deforestation

• Definition of habitat and niche

• Introduction
• Factors Related to Population Growth

Population Interactions

1. Predation (adaptations in organisms to avoid predation)
2. Competition (Interspecific, interference, Competitive exclusion, Competitive release, Gause's Competitive Exclusion Principle)
3. Parasitism 
   ⇒ Types of parasites: Ectoparasites, Endoparasites, Brood parasitism
4. Commensalism
5. Mutualism
6. Amensalism

• Introduction to Ecosystem
• Interactions in the Ecosystem

• Definition of stenothermal, Eurythermal, stenohaline and euryhaline), responses to abiotic factors (regulate, conform, migrate, suspend). Allen’s rule.

• Ecosystems
• Components of the environment - Abiotic and biotic, Productivity, Decomposition, Energy flow, Nutrient cycling
• The function of the Ecosystem:

1. Photosynthetically Active Radiation (PAR), Definition of PAR, 10% Law, standing crop and standing state.
2. Productivity of an ecosystem
3. Concept of trophic level in an ecosystem
4. Energy flow
5. Food chain
6. Food Web
7. Ecological pyramids
8. Decomposition
9. Biogeochemical cycle (Nutrient cycle)
10. Types of ecosystem
11. Ecosystem services ( Benefits)
12. Ecosystem Management

• Primary production
• Productivity
• Types of productivity

1. Primary productivity
   1) Gross primary productivity (GPP)
   2) Net-primary productivity (NPP)
2. Secondary productivity

• Decomposition
• Detritus
• Steps in Decomposition
  (i) Fragmentation
  (ii) Leaching
  (iii) Catabolism
  (iv) Humification
  (v) Mineralisation
• Factors affecting the rate of decomposition

• Introduction
• Trophic Levels of The Ecosystem

• Ecological Pyramids

1. Pyramid of biomass 
2. Pyramid of numbers 
3. Pyramid of energy 

• Limitations of ecological pyramids

Ecological succession

• Classification of ecological succession
  (i) Primary Succession
  (ii) Secondary Succession
• Succession of Plants
• Kinds of plant succession
  (i) Hydrarch Succession
  (ii) Xerarch Succession

• Nutrient Cycles
• Types of Nutrient cycles

Ecological services

• Categories of ecosystem services

1. Supporting services
2. Provisioning services
3. Regulating services
4. Cultural services

Following are the main ecological services: 

• Carbon fixation 
• Oxygen release 
• Pollination 

Patterns of Biodiversity

• Latitudinal and altitudinal gradients
• Species-Area relationships

• Loss of Biodiversity
• Causes of Biodiversity losses
  (i) Habitat loss and fragmentation
  (ii) Overexploitation
  (iii) Alien species invasions
  (iv) Co-extinctions

• Why should we conserve Biodiversity?
  (i) Narrowly utilitarian argument
  (ii) Broadly utilitarian argument
  (iii) Ethical argument
• How do we conserve Biodiversity?
  (i) In-situ methods: Biodiversity Hotspots and Sacred Groves
  (ii) Ex-situ Conservation - Zoological parks, Botanical parks, Wildlife Safari parks

• Ecological Role of Biodiversity
• Economic Role of Biodiversity
• Scientific Role of Biodiversity
• Rivet Popper hypothesis

• Red data book
• Categories in Red Data Book
  (1) Extinct
  (2) Extinct in the wild
  (3) Critically Endangered
  (4) Endangered
  (5) Vulnerable
  (6) Near Threatened
  (7) Least Concern
  (8) Data Deficient
  (9) Not Evaluated

• In-situ Conservation 

• Protected Areas
• National Parks (NP)
• Wild Life Sanctuaries (WLS)
• Biosphere Reserve (BR)
• Sacred Groves

• Ex-Situ Conservation

• Offsite Collections
• Gene Banks