AP Intermediate Botany (BIEAP) cheat sheet

Binomial nomenclature: genus capitalized, species lowercase, both italicized; author citation follows species name (e.g., Mangifera indica L.).

Five-kingdom classification (Whittaker 1969): Monera, Protista, Fungi, Plantae, Animalia - based on cell type, body organization, nutrition, and reproduction.

Algae divisions by pigment: Chlorophyceae (chlorophyll a, b), Phaeophyceae (fucoxanthin, brown), Rhodophyceae (phycoerythrin, red).

Bryophytes: amphibious plants, gametophyte dominant, water required for sperm transfer; sporophyte dependent on gametophyte.

Pteridophytes: first vascular plants, sporophyte dominant, independent gametophyte (prothallus), heterosporous in Selaginella and Salvinia.

Gymnosperms: naked ovules, no ovary/fruit, haploid endosperm; Cycas has coralloid roots with cyanobacteria, Pinus has mycorrhizal roots.

Angiosperms: double fertilization produces diploid zygote and triploid primary endosperm nucleus; ovule becomes seed, ovary becomes fruit.

Fungi: chitinous cell wall, heterotrophic, mycelium of hyphae; symbiotic forms - lichens (alga + fungus) and mycorrhiza (fungus + root).

Viruses: acellular, obligate intracellular parasites with nucleic acid core and protein capsid; TMV has ssRNA, bacteriophage T4 has dsDNA.

Root modifications: tap roots - fusiform, napiform, conical, tuberous; adventitious roots - prop, stilt, pneumatophores, velamen.

Stem modifications: rhizome, tuber, corm, bulb (underground); tendril, thorn, cladode, phylloclade (aerial).

Inflorescence: racemose (acropetal, main axis continues) vs cymose (basipetal, main axis terminates in flower).

Aestivation types: valvate, twisted, imbricate, vexillary; placentation types: marginal, axile, parietal, free-central, basal.

Monocot vs dicot stem: monocot has scattered vascular bundles and no secondary growth; dicot bundles in a ring with cambium.

Stomatal apparatus: guard cells, subsidiary cells, stomatal pore; kidney-shaped in dicots, dumbbell-shaped in grasses.

Xylem: tracheids, vessels, xylem parenchyma, xylem fibres; phloem: sieve tubes, companion cells, phloem parenchyma, phloem fibres.

Secondary growth: vascular cambium adds secondary xylem inside and secondary phloem outside; cork cambium forms periderm.

Tissue systems: epidermal (protection), ground (cortex, pith), vascular (xylem, phloem).

Prokaryotic cell: 70S ribosomes, no membrane-bound organelles, single circular DNA; eukaryotic cell: 80S ribosomes, membrane-bound nucleus.

Endomembrane system: ER, Golgi, lysosomes, vacuoles, plasma membrane; mitochondria and chloroplasts are excluded.

Mitochondria and chloroplasts are semi-autonomous: own DNA, 70S ribosomes, double membrane - endosymbiotic origin.

Fluid mosaic model (Singer & Nicolson): phospholipid bilayer with integral and peripheral proteins, cholesterol modulating fluidity.

Enzymes lower activation energy; competitive inhibitors bind active site, non-competitive inhibitors bind allosteric site.

Protein structure: primary (amino acid sequence), secondary (alpha helix, beta sheet), tertiary (3D folding), quaternary (multiple polypeptides).

Biomolecule tests: Benedict's for reducing sugars, iodine for starch, Biuret for protein, Sudan III for lipids.

Cell cycle: G1, S (DNA replication), G2, M; cytokinesis follows mitosis; meiosis has two divisions with one replication.

Meiosis prophase I substages: leptotene, zygotene (synapsis), pachytene (crossing over), diplotene (chiasmata), diakinesis.

Water potential = solute potential + pressure potential; water moves from higher (less negative) to lower (more negative) water potential.

Plasmolysis occurs when a cell loses water in a hypertonic solution; deplasmolysis is reversal in hypotonic solution.

Transpiration pull-cohesion-tension theory explains xylem ascent of sap; root pressure causes guttation.

Stomatal opening: K+ influx lowers solute potential, water enters guard cells, turgor rises, pore opens.

Photosynthesis: light reaction in thylakoid (PSII, PSI, Z-scheme, photolysis of water, ATP and NADPH); Calvin cycle in stroma.

C4 pathway: PEP carboxylase fixes CO2 into oxaloacetate in mesophyll; bundle-sheath cells run Calvin cycle; low photorespiration.

CAM plants fix CO2 at night as malate, decarboxylate by day; stomata open at night to conserve water.

Limiting factors: Blackman's law of limiting factors; light saturation, CO2 concentration, temperature affect rate.

Respiration: glycolysis in cytoplasm (net 2 ATP, 2 NADH); Krebs cycle in matrix; ETC on inner mitochondrial membrane; oxidative phosphorylation yields ~30-32 ATP per glucose.

Microsporogenesis: microspore mother cell → meiosis → tetrad → microspores → pollen grain with vegetative and generative cells.

Megasporogenesis: megaspore mother cell → meiosis → four megaspores, three degenerate; functional megaspore forms 8-nucleate embryo sac (Polygonum type).

Double fertilization: one male gamete fuses with egg (2n zygote), other with two polar nuclei (3n primary endosperm nucleus).

Endosperm types: nuclear (free nuclei, coconut water), cellular (coconut kernel), helobial; endosperm nourishes embryo.

Embryo development stages: proembryo, globular, heart-shaped, mature embryo with cotyledons, plumule, radicle.

Apomixis: seed formation without fertilization; polyembryony: more than one embryo per seed (e.g., Citrus).

Parthenocarpy: fruit development without fertilization, induced by auxin or gibberellin, seedless fruit.

Seed germination: epigeal (cotyledons above soil) vs hypogeal (cotyledons remain below); requires water, oxygen, suitable temperature.

Plant growth regulators: auxin (apical dominance, rooting), gibberellin (stem elongation), cytokinin (cell division), ABA (stress, dormancy), ethylene (ripening).

Mendel's laws: dominance, segregation (monohybrid 3:1), independent assortment (dihybrid 9:3:3:1).

Test cross: cross with homozygous recessive to determine genotype; back cross: cross with either parent.

Incomplete dominance: intermediate phenotype (Snapdragon, 1:2:1); codominance: both alleles expressed (AB blood group).

Multiple alleles: ABO blood group has IA, IB, i alleles; a single individual carries only two.

Linkage: genes on same chromosome tend to be inherited together; recombination frequency proportional to distance.

Sex determination: XX-XY (humans), XX-XO (grasshoppers), ZZ-ZW (birds); plants like Melandrium show XX-XY.

Chromosomal disorders: Down syndrome (trisomy 21), Turner (XO), Klinefelter (XXY); caused by non-disjunction.

Pedigree analysis: autosomal dominant appears in every generation; autosomal recessive skips generations; X-linked recessive affects males more.

Mutations: point (substitution, deletion, insertion) vs chromosomal (deletion, duplication, inversion, translocation).

DNA structure (Watson-Crick 1953): antiparallel double helix, base pairing A-T (2 H-bonds), G-C (3 H-bonds), major and minor grooves.

DNA replication is semi-conservative (Meselson-Stahl), bidirectional, requires helicase, primase, DNA polymerase, ligase.

Central dogma: DNA → RNA (transcription) → protein (translation); reverse transcription in retroviruses.

Transcription in prokaryotes: RNA polymerase with sigma factor; eukaryotes: RNA polymerase I (rRNA), II (mRNA), III (tRNA).

Genetic code: triplet, degenerate, non-overlapping, universal; AUG start codon (methionine), UAA, UAG, UGA stop codons.

Lac operon: repressor binds operator without lactose; lactose acts as inducer; structural genes z, y, a.

Recombinant DNA: restriction enzymes (EcoRI, HindIII) cut palindromic sequences; ligase joins; vectors include plasmids and bacteriophages.

PCR: denaturation, annealing, extension using Taq polymerase; used to amplify DNA.

Applications: Bt cotton (Bt toxin gene), Golden Rice (beta-carotene), gene therapy, DNA fingerprinting (VNTR).

Population growth: exponential (r-selected, unlimited resources) vs logistic (K-selected, carrying capacity K).

Species interactions: mutualism (+,+), commensalism (+,0), parasitism (+,−), predation (+,−), competition (−,−).

Ecological pyramids: number, biomass, energy; energy pyramid is always upright (10% law, Lindeman).

Succession: primary (bare rock) vs secondary (after disturbance); hydrarch (wet to dry) and xerarch (dry to wet) series.

Biogeochemical cycles: carbon, nitrogen (fixation, nitrification, denitrification), phosphorus (no gaseous phase).

Biodiversity hotspots in India: Western Ghats, Eastern Himalaya, Indo-Burma, Sundaland (Nicobar).

In-situ conservation: national parks, biosphere reserves; ex-situ: seed banks, botanical gardens, zoos.

Plant evolution: algae → bryophytes → pteridophytes → gymnosperms → angiosperms; trend toward sporophyte dominance and vascular tissue.

Pollution indicators: lichens indicate SO2; eutrophication from nitrate and phosphate runoff.

Crop improvement methods: selection, hybridization (hybrid vigour/heterosis), mutation breeding, polyploidy, genetic engineering.

Plant tissue culture: callus induction from explant, auxin/cytokinin ratio controls root vs shoot; micropropagation produces clones.

Biofertilizers: Rhizobium (legume nodules), Azotobacter (free-living), Azospirillum, mycorrhiza (phosphorus uptake), blue-green algae.

Plant pathology: rust (Puccinia), smut (Ustilago), blight (Xanthomonas), mosaic (virus) - symptoms and causal agents.

Medicinal plants: Cinchona (quinine), Papaver (morphine), Rauwolfia (reserpine), Digitalis (digitoxin).

Herbarium technique: collection, pressing, drying, mounting, labeling with scientific name, locality, collector, date.

Microscopy skills: magnification = eyepiece × objective; section cutting, staining with safranin/fast green.

Experimental design: control group, replicates, variables; colorimetry and titration for quantitative estimation.

Food preservation and spoilage: microbial growth controlled by drying, salting, refrigeration, canning.