Interactive diagrams — Class 12 Biology

98 diagrams · tap a card, then tap any label.

Ch 1 · Sexual Reproduction in Flowering Plants

L.S. of a flowerFig 1.1Stamen and 3-D cut section of antherFig 1.2T.S. of a young antherFig 1.3aMicrosporangium: wall layers & microsporogenesisFig 1.3bPollen grain (2-celled and 3-celled)Fig 1.5Anatropous ovule (megasporangium)Fig 1.7dMature embryo sac — 7 cells, 8 nucleiFig 1.8cMegasporogenesis → embryo sac (step by step)Fig 1.8a, bKinds of pollinationFig 1.9Pollen–pistil interaction: path of the pollen tubeFig 1.12Double fertilisation (syngamy + triple fusion)Fig 1.12e, 1.13aEmbryo development in a dicot (embryogeny)Fig 1.13bTypical dicot embryoFig 1.14aL.S. of a grass (monocot) embryoFig 1.14bDicot seed (bean)Fig 1.15aMonocot seed (maize grain) L.S.Fig 1.15aFalse fruits: apple and strawberryFig 1.15bArtificial hybridisation: emasculation & bagging

Ch 2 · Human Reproduction

Seminiferous tubule (sectional view)Fig 2.2, 2.5Structure of a spermFig 2.6Section of ovary: follicles to corpus luteumFig 2.7Menstrual cycle (28 days)Fig 2.9 (schematic)Gametogenesis: spermatogenesis vs oogenesisFig 2.8Fertilisation, cleavage and implantationFig 2.11

Ch 3 · Reproductive Health

Where contraceptives and ART actFigs 3.1–3.4

Ch 4 · Principles of Inheritance and Variation

Monohybrid cross (Punnett square)Figs 4.3–4.4Dihybrid cross (9:3:3:1)Fig 4.7Sex determination in humans (XY)Fig 4.12

Ch 5 · Molecular Basis of Inheritance

DNA double helix (Watson–Crick model)Fig 5.3Nucleosome and beads-on-stringFig 5.4Griffith's transformation experiment (1928)Hershey–Chase experiment (1952)Fig 5.5Meselson and Stahl's experiment (1958)Fig 5.7Replicating forkFig 5.8Transcription unit, transcription and RNA processingFig 5.9–5.11tRNA — the adapter moleculeFig 5.12Translation on the ribosomeFig 5.13The lac operonFig 5.14DNA fingerprinting (VNTR)Fig 5.16

Ch 6 · Evolution

Miller's experiment (1953)Fig 6.1Homologous organs: vertebrate forelimbsFig 6.3 (b)White- and dark-winged moths (England)Fig 6.4Darwin's finches — adaptive radiationFig 6.5Adaptive radiation of Australian marsupialsFig 6.6Convergent evolution: placental vs marsupial look-alikesFig 6.7Three types of natural selectionFig 6.8Origin and evolution of man (NCERT 6.9)Section 6.9

Ch 7 · Human Health and Disease

Life cycle of Plasmodium (malaria)Fig 7.1Structure of an antibody moleculeFig 7.4Lymphoid organs in the human bodyFig 7.5Replication of a retrovirus (HIV)Fig 7.6Commonly abused drugs and their sourcesFigs 7.7–7.11

Ch 8 · Microbes in Human Welfare

Sewage treatment plantFig 8.6A typical biogas plantFig 8.8Biocontrol agents & biofertilisersUseful products from microbes

Ch 9 · Biotechnology: Principles and Processes

EcoRI cut, sticky ends & recombinant DNAFig 9.1E. coli cloning vector pBR322Fig 9.4Blue–white selection (insertional inactivation)Agarose gel electrophoresisFig 9.3Polymerase chain reaction (PCR)Fig 9.6Sparged stirred-tank bioreactorFig 9.7Steps of recombinant DNA technologyFig 9.2

Ch 10 · Biotechnology and its Applications

Bt toxin: how it kills the pestRNAi: nematode-resistant tobaccoFig 10.2Pro-insulin → insulinFig 10.3Making human insulin in E. coliGene therapy for ADA deficiencyMolecular diagnosis: PCR, probe, ELISATissue culture: three usesTransgenic animals: 5 uses

Ch 11 · Organisms and Populations

Age pyramidsFig 11.1What changes population densityFig 11.2Population growth curvesFig 11.3Population interactions (+, −, 0)Table 11.1Fig and wasp: mutualismFig 11.4Ophrys orchid: sexual deceitFig 11.5

Ch 12 · Ecosystem

Pond ecosystem — structureSection 12.1Stratification in a forestSection 12.1Productivity: GPP − R = NPPSection 12.2Decomposition cycleFig 12.1Trophic levels in an ecosystemFig 12.2Food chains (GFC, DFC) and food webSection 12.4Energy flow through trophic levelsFig 12.3Pyramid of numbers — grasslandFig 12.4 (a)Pyramid of biomass (upright)Fig 12.4 (b)Inverted pyramid of biomass — seaFig 12.4 (c)Pyramid of energy (always upright)Fig 12.4 (d)

Ch 13 · Biodiversity and Conservation

Levels of biodiversitySection 13.1Species in major taxa (proportions)Fig 13.1Latitudinal gradient in diversitySection 13.1.2Species–area relationshipFig 13.2Rivet popper hypothesis (Paul Ehrlich)Section 13.1.3Threatened species and the Sixth ExtinctionSection 13.1.4Causes of biodiversity loss — the Evil QuartetSection 13.1.4Why conserve biodiversity?Section 13.2.1In situ and ex situ conservationSection 13.2.2Biodiversity hotspots (India’s three)Section 13.2.2