Important scientists
| Scientist | Famous for | Chapter |
|---|---|---|
| Gregor Mendel | Laws of inheritance (pea plants) | 4 |
| Sutton and Boveri | Chromosomal theory of inheritance | 4 |
| T.H. Morgan | Linkage, using Drosophila | 4 |
| Alfred Sturtevant | First gene maps | 4 |
| Frederick Griffith | Transformation experiment | 5 |
| Avery, MacLeod and McCarty | DNA is the transforming principle | 5 |
| Hershey and Chase | DNA is the genetic material (³²P, ³⁵S) | 5 |
| Watson and Crick | Double helix model of DNA (1953) | 5 |
| Erwin Chargaff | A = T and G = C | 5 |
| Meselson and Stahl | Semi-conservative replication (¹⁵N) | 5 |
| Jacob and Monod | lac operon | 5 |
| Alec Jeffreys | DNA fingerprinting | 5 |
| Oparin and Haldane | Chemical evolution | 6 |
| Stanley Miller | Amino acids from simple gases | 6 |
| Charles Darwin | Natural selection | 6 |
| Hugo de Vries | Mutation theory (evening primrose) | 6 |
| Alexander Fleming | Penicillin | 8 |
| Stanley Cohen and Herbert Boyer | First recombinant DNA (1972) | 9 |
| Verhulst and Pearl | Logistic growth | 11 |
| Gause | Competitive exclusion principle | 11 |
| MacArthur | Resource partitioning (warblers) | 11 |
| Lindeman | 10% law of energy transfer | 12 |
| Edward Wilson | Popularised the term "biodiversity" | 13 |
| Alexander von Humboldt | Species–area relationship | 13 |
| David Tilman | More species = more stable ecosystem | 13 |
| Paul Ehrlich | Rivet popper hypothesis | 13 |
| Robert May | Estimated ~7 million species on Earth | 13 |
Important abbreviations
| Short | Full form |
|---|---|
| ART | Assisted Reproductive Technologies |
| IVF | In Vitro Fertilisation |
| GIFT | Gamete Intra Fallopian Transfer |
| ZIFT | Zygote Intra Fallopian Transfer |
| IUT | Intra Uterine Transfer |
| ICSI | Intra Cytoplasmic Sperm Injection |
| IUI | Intra Uterine Insemination |
| IUD | Intra Uterine Device |
| MTP | Medical Termination of Pregnancy |
| STI | Sexually Transmitted Infection |
| RCH | Reproductive and Child Health Care |
| hCG | Human Chorionic Gonadotropin |
| VNTR | Variable Number of Tandem Repeats |
| SNP | Single Nucleotide Polymorphism |
| EST | Expressed Sequence Tag |
| BAC / YAC | Bacterial / Yeast Artificial Chromosome |
| HGP | Human Genome Project |
| PCR | Polymerase Chain Reaction |
| ELISA | Enzyme-Linked Immunosorbent Assay |
| AIDS | Acquired Immuno Deficiency Syndrome |
| HIV | Human Immunodeficiency Virus |
| MALT | Mucosa-Associated Lymphoid Tissue |
| CMI | Cell-Mediated Immunity |
| NACO | National AIDS Control Organisation |
| LAB | Lactic Acid Bacteria |
| BOD | Biochemical Oxygen Demand |
| STP | Sewage Treatment Plant |
| IARI | Indian Agricultural Research Institute |
| KVIC | Khadi and Village Industries Commission |
| IPM | Integrated Pest Management |
| GMO | Genetically Modified Organism |
| GEAC | Genetic Engineering Approval Committee |
| ADA | Adenosine Deaminase |
| EFB | European Federation of Biotechnology |
| GPP / NPP | Gross / Net Primary Productivity |
| PAR | Photosynthetically Active Radiation |
| IUCN | International Union for Conservation of Nature |
Numbers you must remember
| Fact | Number |
|---|---|
| Embryo sac | 7 cells, 8 nuclei |
| Scrotum is cooler than the body by | 2–2.5 °C |
| Sperms per ejaculation | 200–300 million |
| Primary follicles left per ovary at puberty | 60,000–80,000 |
| Emergency contraception works within | 72 hours |
| MTP is safest up to | 12 weeks |
| Monohybrid / dihybrid F2 ratio | 3 : 1 / 9 : 3 : 3 : 1 |
| DNA: bp per turn, pitch, gap | 10 bp, 3.4 nm, 0.34 nm |
| Human DNA length | ~2.2 m |
| Human genome | 3164.7 million bp, ~30,000 genes |
| Codons | 64 (61 amino acids + 3 stop) |
| Energy passed to the next trophic level | ~10% |
| Earth's NPP / oceans' NPP | 170 / 55 billion tons per year |
| India's share of land / species | 2.4% / 8.1% |
| Biodiversity hotspots (world / India) | 34 / 3 |
Top memory tricks
| Topic | Trick |
|---|---|
| Microsporangium wall layers | "Every Elephant Makes Tea" → Epidermis, Endothecium, Middle layers, Tapetum |
| Male duct path | "Sita Rides Very Easy Vans Every Utsav" |
| Embryo sac | 3 + 1 + 3 (egg apparatus + central cell + antipodals) |
| Incurable STIs | "H, H, H" → Herpes, Hepatitis B, HIV |
| Mendel's laws | DSI → Dominance, Segregation, Independent assortment |
| ABO blood groups | 3-6-4 → 3 alleles, 6 genotypes, 4 blood groups |
| Purines | "Pure As Gold" → A and G |
| RNA polymerases | R-M-T = 1-2-3 |
| lac operon genes | "Z-Y-A → Big Party Tonight" → β-galactosidase, permease, transacetylase |
| Hardy–Weinberg factors | "My Great Man Ran Now" |
| Innate immunity barriers | PPCC → physical, physiological, cellular, cytokine |
| PCR steps | "Heat–Stick–Build" → denaturation, annealing, extension |
| Decomposition steps | "Frogs Love Catching Happy Mosquitoes" |
| Evil Quartet | HOAC → Habitat loss, Over-exploitation, Alien species, Co-extinction |
Diagrams to practise
Board exams often ask you to draw and label these. Practise each one from your NCERT textbook at least 3 times:
- T.S. of an anther and the structure of a pollen grain
- Embryo sac (7 cells, 8 nuclei)
- L.S. of a flower showing pollen tube growth
- Human male and female reproductive systems
- Sperm and ovum
- Menstrual cycle hormone graph
- Seminiferous tubule and Graafian follicle
- DNA double helix and the replication fork
- lac operon (with and without lactose)
- Antibody structure (H₂L₂)
- pBR322 vector
- Growth curves (J and S) and age pyramids
- Ecological pyramids