CBSE Class 12 Biology

CBSE class 12 biology NCERT Solutions, latest sample papers with solutions, projects, past year boards question papers solved, latest syllabus and other useful study material, free download in pdf study material for biology, practice to get better marks in examinations. all study material has been prepared based on latest guidelines, term examination pattern and blueprint issued by cbse and ncert

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Free study material for Biology

Class 12 Biology: Interactive Unit Workbenches & Diagrammatic Simulators

Visual Workbenches & Drag-and-Drop Concept Builders

Choose a Unit below to interact with anatomical labelers, pathway sequencers, and ecological pyramid builders.

Interactive Labeler: Female Gametophyte (Embryo Sac)

Drag or Click each anatomical component to match its specific position and ploidy.

Available Cell Structures & Nuclei (Click or Drag):

3 Antipodal Cells (Haploid n) Central Cell with 2 Polar Nuclei (2n) 2 Synergids + Filiform Apparatus (n) Single Female Egg Cell / Oosphere (n)
1. Chalazal Pole End: Three cells grouped together providing nourishment support.
Drop Chalazal Cells here
2. Large Central Region: Contains the two polar nuclei before triple fusion.
Drop Central Region here
3. Micropylar Lateral Flanks: Special finger-like cellular thickenings that guide the pollen tube.
Drop Guiding Cells here
4. Micropylar Core: The primary female haploid gamete situated between the synergids.
Drop Female Gamete here
 

Replication Fork Molecular Enzyme Matcher

Assign the correct enzyme or molecular intermediate to its precise functional role during DNA replication.

Enzymes & Replication Strands:

DNA Helicase DNA Polymerase III Okazaki Fragments (Lagging Strand) DNA Ligase
1. Unwinding Enzyme: Breaks hydrogen bonds between base pairs to open the double helix at ori.
Drop Unwinding Enzyme
2. Main Polymerizing Enzyme: Catalyzes fast 5' → 3' phosphodiester polymerization of dNTPs.
Drop Synthesis Enzyme
3. Discontinuous Segments: Short newly synthesized DNA pieces on the template with 5' → 3' polarity.
Drop Discontinuous Pieces
4. Molecular Glue: Joins discontinuous nicks in the sugar-phosphate backbone into a continuous strand.
Drop Sealing Enzyme
 

Sequential Pathway: Malarial Parasite (Plasmodium) Life Cycle

Place the developmental stages in correct chronological order from mosquito bite to vector transmission.

Life Cycle Stages (Re-order Chronologically):

1. Infectious Sporozoites injected with mosquito saliva 2. Asexual Schizogony inside Human Liver Parenchymal Cells 3. RBC Rupture & Toxic Haemozoin Release (Chills & Fever) 4. Sexual Gametocytes taken up during subsequent Mosquito Bite
Stage A (Primary Entry): Motile parasite forms enter human bloodstream during female Anopheles feeding.
Drop Initial Inoculation
Stage B (Tissue Phase): Parasites reach hepatic vessels and multiply asexually before entering circulation.
Drop Hepatic Multiplication
Stage C (Erythrocytic Cycle): Merozoites invade red blood cells, bursting them and causing clinical paroxysms.
Drop Toxin & RBC Phase
Stage D (Sexual Cycle in Vector): Fertilization and development occur inside the mosquito gut walls.
Drop Vector Gametogenesis
 

Recombinant DNA Technology (rDNA) Process Workflow

Construct the correct genetic engineering process pathway from cell lysis to bioreactor harvesting.

Biotechnology Process Steps:

Step 1: Cell Lysis & Chilled Ethanol DNA Precipitation Step 2: Restriction Endonuclease Cleavage (Sticky Ends) Step 3: Ligation with Plasmid Vector using T4 DNA Ligase Step 4: Competent Host Transformation & Bioreactor Scaling
Phase 1: Isolating pure macromolecular genomic DNA free from RNA and proteins.
Drop DNA Isolation Step
Phase 2: Cutting both source DNA and cloning vector at identical palindromic recognition sites.
Drop Molecular Scissors Step
Phase 3: Splicing foreign gene of interest into pBR322 / vector backbone.
Drop Ligation Step
Phase 4: Heat-shock insertion into E. coli followed by continuous stirred-tank fermentation.
Drop Expression Step
 

Ecological 10% Energy Pyramid Architecture

Apply Lindeman's 10% Energy Law starting with 10,000 Joules of captured sunlight at the producer level.

Trophic Energy Blocks (Drag to correct Pyramid Tier):

T1: Primary Producers (10,000 J) T2: Herbivores / Primary Consumers (1,000 J) T3: Secondary Consumers / Small Carnivores (100 J) T4: Top Apex Carnivores (10 J)
Top Tier (T4): Apex Predators (Eagle / Lion) receiving lowest net usable energy.
Drop Tier 4 Block
Third Tier (T3): Primary Carnivores (Frogs / Small birds) consuming herbivores.
Drop Tier 3 Block
Second Tier (T2): Primary Consumers (Insects / Deer) feeding directly on plants.
Drop Tier 2 Block
Base Tier (T1): Autotrophic Green Vegetation fixing radiant solar energy.
Drop Base Tier Block
 

The Biology curriculum now focusses more on conceptual application. Almost 50% of the paper now has Competency-Based questions. Whether you are aiming for a perfect 70/70 in your boards or building a foundation for medical entrances like NEET, our Class 12 Biology study material and specially mock tests are the best resoource for you. We have provided the latest CBSE exam pattern papers, perfectly labeled diagrams, and chapter-wise weightage to help you get more marks in exams. Download our teacher preapred notes and sample papers to start your preparation and get the best rank.

Unit-Wise Weightage - Visual Breakdown

Tap a unit below to see its high-focus topics for the 2026-27 exam.

 
 

Figures reflect the 70-mark CBSE Class 12 Biology (Code 044) theory paper for 2026-27. An additional 30 marks are allotted to Practicals (experiments, slide preparation, spotting, project work and viva).

The paper consists of 33 questions divided into five sections (A to E):

Section A: 16 Objective-type questions (MCQs and Assertion-Reason).

Section B & C: Very Short and Short Answer questions focusing on definitions and processes.

Section D: Two Case-Based questions (4 marks each) that test your ability to apply theory to real-life biological scenarios.

Section E: Three Long Answer questions (5 marks each). In this section diagram skills are tested.

 

CBSE Class 12 Biology Syllabus and Examination Structure

THEORY

I. Reproduction (Periods 35)

Reproduction in organisms: Reproduction, a characteristic feature of all organisms for continuation of species; Modes of reproduction – Asexual and sexual; Asexual reproduction; Modes- Binary fission, sporulation, budding, gemmule, fragmentation; vegetative propagation in plants.

Sexual reproduction in flowering plants: Flower structure; Development of male and female gametophytes; Pollination–types, agencies and examples; Outbreedings 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 and fruit formation.

Human Reproduction: Male and female reproductive systems; Microscopic anatomy of testis and ovary; Gametogenesis- spermatogenesis & oogenesis; Menstrual cycle; Fertilisation, embryo development upto blastocyst formation, implantation; Pregnancy and placenta formation (Elementary idea); Parturition (Elementary idea); Lactation (Elementary idea).

Reproductive health: Need for reproductive health and prevention of sexually transmitted diseases (STD); 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).

II. Genetics and Evolution (Periods 45)

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, 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.

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 genome project; DNA finger printing.

Evolution: Origin of life; Biological evolution and evidences for biological evolution (Paleontological, 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, types of natural selection; Gene flow and genetic dirft; Hardy- Weinberg’s principle;Adaptive Radiation; Human evolution.

III Biology and Human Welfare (Periods 35)

Health and Disease: Pathogens; parasites causing human diseases (Malaria, Filariasis, Ascariasis, Typhoid, Pneumonia, common cold, amoebiasis, ring worm); Basic concepts of immunology–vaccines; Cancer, HIV and AIDs; Adolescence, drug and alcohol abuse.

Improvement in food production: Plant breeding, tissue culture, single cell protein, Biofortification; Apiculture and Animal husbandry.

Microbes in human welfare: In household food processing, industrial production, sewage treatment, energy generation and as biocontrol agents and biofertilizers.

IV Biotechnology and Its Applications (Periods 30)

Principles and process of Biotechnology: Genetic engineering (Recombinant DNA technology). Application of Biotechnology in health and agriculture: Human insulin and vaccine production, gene therapy; Genetically modified organisms- Bt crops; Transgenic Animals; Biosafety issues– Biopiracy and patents.

V Ecology and environment (Periods 35)

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.

Ecosystems: Patterns, components; productivity and decomposition; Energy flow; Pyramids of number, biomass, energy; Nutrient cycling (carbon and phosphorous); Ecological succession; Ecological Services– Carbon fixation, pollination, oxygen release.

Biodiversity and its conservation: Concept of Biodiversity; Patterns of Biodiversity; Importance of Biodiversity; Loss of Biodiversity; Biodiversity conservation; Hotspots, endangered organisms, extinction, Red Data Book, biosphere reserves, National parks and sanctuaries.

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 global warming; Ozone depletion; Deforestation;Any three case studies as success stories addressing environmental issues.

CBSE Class 12 Biology Practicals Syllabus and Examination structure (Total Periods = 60)

List of Experiments

  1. Study pollen germination on a slide.
  1. Collect and study soil from at least two different sites and study them for texture, moisture content, pH and water holding capacity of soil. Correlate with the kinds of plants found in them.
  2. Collect water from two different water bodies around you and study them for pH, clarity and presence of any living organisms.
  3. Study the presence of suspended particulate matter in air at the two widely different sites.
  1. Study of plant population density by quadrate method.
  1. Study of plant population frequency by quadrate method.
  1. Prepare a temporary mount of onion root tip to study mitosis.
  1. To study the effect of the different temperatures and three different pH on the activity of salivary amylase on starch.

Study/observation of the following (Spotting)

  1. Flowers adapted to pollination by different agencies (wind, insect).
  1. Pollen germination on stigma through a permanent slide.
  1. Identification of stages of gamete development i.e. T.S. testis and T.S. ovary through permanent slides (from any mammal).
  2. Meiosis in onion bud cell or grass hopper testis through permanent slides.
  1. T.S. of blastula through permanent slides.
  1. Mendelian inheritance using seeds of different colour/size of any plant.
  1. Prepared pedigree charts of genetic traits such as rolling of tongue, blood groups, widow’s peak, colour blindness.
  2. Exercise on controlled pollination – Emasculation, tagging and bagging.
  1. Identification of common disease causing organisms like Ascaris, Entamoeba, Plasmodium, ringworm through permanent slides or specimens. Comment on symptoms of diseases that they cause.
  2. Two plants and two animals found in xerophytic conditions. Comment upon their morphological adaptations.
  3. Plants and animals found in aquatic conditions. Comment upon their morphological

Expert Tips for 70/70

Stick to NCERT: 95% of the board questions come directly from NCERT textbook. Pay attention to the "Summary" and "In-text" questions.

Diagram Accuracy: Always use a sharp pencil for diagrams. Ensure all labels are on one side of the drawing which helps to maintain neatness.

Keyword Integration: Use biological terms to secure full marks in descriptive answers.