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- Country FlagsIdentify the country from its flag. Reveal, then self-grade.
- World CapitalsCapital cities around the world
- Middle AgesA time of castles, cold stone and some truly unfair plagues.
- General KnowledgeAcross various topics including history, science, geography, culture, and more
- Dogs Recognize breeds. Learn about behaviors, anatomy, and origins of man's best friend.
- Star WarsInto the galaxy far, far away you go. Your Star Wars knowledge, tested it will be.
- Electronic Structure and Periodic Properties (Chemistry)Recall cards on the electronic structure of atoms and periodic trends: electromagnetic energy (wavelength, frequency, the speed of light, blackbody radiation, quantization, photons, the photoelectric effect, line spectra, the Rydberg formula, and wave-particle duality); the Bohr model of hydrogen (stationary states, quantized orbital energies, ground and excited states, the Bohr radius, and ionization); the development of quantum theory (de Broglie wavelength, the Heisenberg uncertainty principle, wavefunctions and atomic orbitals, the four quantum numbers, the Pauli exclusion principle, and orbital shapes); electron configurations (the Aufbau principle, Hund's rule, subshell filling order, valence and core electrons, noble gas notation, ion configurations, and the periodic table blocks); and periodic variations (atomic and ionic radii, effective nuclear charge, ionization energy, electron affinity, and metallic character).
- Animal Nutrition and the Digestive SystemRecall cards on animal nutrition and digestion: dietary categories (herbivores, carnivores, omnivores); digestive-system types (gastrovascular cavity, alimentary canal, monogastric, avian, ruminant, and pseudo-ruminant); the vertebrate digestive organs from oral cavity to anus and the accessory organs (liver, pancreas, gallbladder); essential nutrients, the vitamins and minerals with their functions and deficiency diseases; ATP and energy production; the four digestive processes (ingestion, digestion, absorption, elimination) with carbohydrate, protein, and lipid digestion; and neural and hormonal regulation of digestion.
- BirdsRecognize and answer trivia about birds
- Population and Community EcologyRecall cards on population and community ecology: population demography (size, density, dispersion patterns, quadrat and mark-recapture sampling, life tables, and Type I, II, and III survivorship curves); life histories and natural selection (energy budgets, fecundity, semelparity versus iteroparity, and the cost of reproduction); environmental limits to growth (exponential J-curves, the per capita rate of increase, carrying capacity, and logistic growth); population dynamics (density-dependent versus density-independent regulation and K- versus r-selection); human population growth and age structure; community ecology (predation and the lynx-hare cycle, defenses and mimicry, competitive exclusion, symbiosis, foundation and keystone species, invasive species, and succession); and behavioral biology (innate versus learned behavior, kinesis and taxis, fixed action patterns, migration, foraging, communication, mating systems and sexual selection, conditioning, and kin selection and altruism).
- Soil and Plant NutritionRecall cards on soil and plant nutrition: the essential elements and the nine macronutrients and the micronutrients, their roles and deficiency symptoms, and hydroponics; the composition, particle sizes, and formation factors of soil, humus, and the soil profile horizons; and nutritional adaptations including biological nitrogen fixation, rhizobia and nodules, mycorrhizae, epiphytes, parasitic and saprophytic plants, and insectivorous plants.
- AnimalsThe animal kingdom, including mammals, birds, reptiles, marine life, and wildlife facts
- ComicsComic books, graphic novels, superheroes, manga, and comic book creators
- Evolution and the Origin of SpeciesRecall cards on evolution and speciation: understanding evolution (natural selection and its three conditions, descent with modification, Darwin and Wallace, the Galapagos finches and the Grants' study, sources of genetic variation, adaptation, divergent versus convergent evolution); the evidence for evolution (fossil record, homologous and analogous and vestigial structures, embryology, biogeography and Pangaea, molecular and genetic evidence, gene duplication); common misconceptions (theory in science, evolution acting on populations, origin of life, goal-direction, antibiotic resistance); the formation of new species (the biological species concept, speciation, reproductive isolation, allopatric versus sympatric speciation, dispersal and vicariance, adaptive radiation, auto- and allopolyploidy, prezygotic and postzygotic barriers); and reconnection and speciation rates (hybrid zones, reinforcement, fusion, and stability, hybrid fitness, gradualism versus punctuated equilibrium).
- General HistoryWorld history, including ancient civilizations, wars, historical figures, and important events
- Transition Metals and Coordination Chemistry (Chemistry)Recall cards on the transition metals and coordination chemistry: the properties of the transition metals and inner transition metals (lanthanides and actinides), their electron configurations, oxidation states, and periodic trends; the occurrence, extraction, and refining of transition metals (roasting, smelting, the blast furnace, steelmaking, copper extraction, and silver hydrometallurgy); the preparation and chemistry of transition metal halides, oxides, hydroxides, and carbonates; coordination compounds and complexes (ligands, denticity, chelates, coordination number and geometry, nomenclature, and the many kinds of isomerism); the biological and industrial roles of coordination compounds (hemoglobin, chlorophyll, cisplatin, EDTA, and catalysis); and crystal field theory, including octahedral, tetrahedral, and square planar d-orbital splitting, high-spin versus low-spin complexes, the spectrochemical series, and the origins of color and magnetism in coordination compounds.
- Representative Metals, Metalloids, and Nonmetals (Chemistry)Recall cards on the descriptive chemistry of the representative elements: periodicity and the periodic behavior of the representative metals (alkali, alkaline earth, group 12, and the metals of groups 13 to 15, plus the inert pair effect and allotropes); the occurrence and preparation of the representative metals (electrolysis in the Downs and Hall-Heroult cells, and chemical reduction such as the Pidgeon process); the structure and properties of the six metalloids (boron, silicon, germanium, arsenic, antimony, and tellurium) and their oxides, halides, and silicates; the structure and properties of the nonmetals (carbon allotropes, phosphorus and sulfur allotropes, and periodic trends); hydrogen and its compounds (isotopes, preparation, ammonia and the Haber process, the hydrogen halides); carbonates and hydrogen carbonates; and the occurrence, preparation, and properties of nitrogen, phosphorus, oxygen (including ozone, oxides, peroxides, superoxides, and hydroxides), sulfur, the halogens, and the noble gases.
- Science GeneralScience and nature, including biology, chemistry, physics, and the natural world
- ComputersComputer science, programming, hardware, software, and technology
- VertebratesRecall cards on the vertebrates and their chordate kin: the five chordate characteristics and the invertebrate lancelets and tunicates; the jawless hagfishes and lampreys and the jawed cartilaginous and bony fishes; the amphibians with their moist skin and metamorphosis; the amniote reptiles, from the amniotic egg and temporal fenestrae to crocodilians, tuataras, squamates, and turtles; the endothermic birds with their feathers, flight muscles, and air-sac lungs; the mammals with hair, mammary glands, and the three-boned middle ear across monotremes, marsupials, and eutherians; and the evolution of the primates through monkeys, apes, and the hominin lineage to Homo sapiens.
- Nervous System Infections (Microbiology)Recall cards on the nervous system infections of microbiology. Anatomy: the central and peripheral nervous systems, the meninges (dura, arachnoid, and pia mater), cerebrospinal fluid, the blood-brain barrier, neurons and glial cells, and the signs of meningitis, encephalitis, and meningoencephalitis. Bacterial diseases: meningococcal, pneumococcal, Haemophilus influenzae type b, neonatal, and Listeria meningitis, tetanus, botulism, and Hansen's disease (leprosy). Acellular diseases: viral meningitis, the arboviral and equine encephalitides, Japanese encephalitis, West Nile virus, Zika, poliomyelitis, rabies, and the prion diseases (scrapie, mad cow disease, and kuru). And fungal and parasitic diseases: cryptococcal meningitis, the amoebic encephalitides, African sleeping sickness, neurotoxoplasmosis, and neurocysticercosis.
- Digestive System Infections (Microbiology)Recall cards on the digestive system infections of microbiology. Anatomy and normal microbiota: the gastrointestinal tract from mouth to anus, the teeth and salivary glands, the small and large intestine, and the gut microbiota with their vitamin production, competitive exclusion, and the barriers of stomach acid, lysozyme, and mucus. Diseases of the mouth: dental caries, plaque and tartar, gingivitis and periodontitis, oral thrush, and mumps. Bacterial infections of the gastrointestinal tract: staphylococcal food poisoning, salmonellosis and typhoid fever, shigellosis, the pathogenic E. coli groups, cholera, Vibrio, Campylobacter, Helicobacter pylori and peptic ulcers, and Clostridioides difficile. Viral infections: rotavirus, norovirus, astrovirus, and hepatitis A through E. Protozoan infections: giardiasis, cryptosporidiosis, amoebiasis, and cyclosporiasis. And helminthic infections: roundworms, tapeworms, and flukes.
- Chemical Bonding and Molecular Geometry (Chemistry)Recall cards on chemical bonding and molecular shape: ionic bonding (ions, cations and anions, ionic bonds and the properties of ionic solids, cation and anion formation rules, and lattice arrangement); covalent bonding (shared electron pairs, bond length, the properties of covalent compounds, pure versus polar covalent bonds, and electronegativity and its periodic trends); Lewis symbols and structures (lone and bonding pairs, the octet rule and its exceptions, single, double, and triple bonds, and free radicals, electron-deficient, and hypervalent molecules); formal charges and resonance (the formal-charge formula, structure selection, and resonance forms and hybrids); the strengths of ionic and covalent bonds (bond energy, bond order, reaction enthalpy from bond energies, lattice energy, and the Born-Haber cycle); and molecular structure and polarity (VSEPR theory, the five electron-pair geometries and their bond angles, lone-pair effects, bond dipole moments, and molecular polarity).
- Respiratory System Infections (Microbiology)Recall cards on the respiratory system infections of microbiology. Anatomy and normal microbiota: the nares, nasal cavity, sinuses, pharynx and its regions, larynx, trachea, bronchi, bronchioles, and alveoli, plus the defenses of the mucociliary escalator, goblet cells, alveolar macrophages, secretory IgA, lysozyme, and defensins, and the naming of inflammations from rhinitis to pneumonia. Bacterial infections: strep throat and scarlet fever, rheumatic fever, otitis media, diphtheria, and the bacterial pneumonias caused by Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella, Mycoplasma, the chlamydiae, Legionella, and Coxiella, along with pertussis and tuberculosis. Viral infections: the common cold, influenza and its antigenic drift and shift, RSV, SARS and MERS, measles, rubella, and varicella-zoster. And the respiratory mycoses: histoplasmosis, coccidioidomycosis, blastomycosis, aspergillosis, Pneumocystis pneumonia, and cryptococcosis.
- Solutions and Colloids (Chemistry)Recall cards on solutions and colloids: the dissolution process (solute and solvent, the spontaneity and entropy of solution formation, ideal solutions, the three intermolecular attractions involved, and endothermic versus exothermic dissolving); electrolytes (strong, weak, and nonelectrolytes, dissociation, ion-dipole attraction, and covalent compounds that ionize by reacting with water); solubility (saturated, unsaturated, and supersaturated solutions, Henry's law for gases, miscibility, and the temperature dependence of solubility); colligative properties (mole fraction and molality, Raoult's law, vapor pressure lowering, boiling point elevation and freezing point depression with their constants, osmosis and osmotic pressure, and the van't Hoff factor); and colloids (the dispersed phase and dispersion medium, the Tyndall effect, sols, aerosols, emulsions, gels and foams, emulsifying agents, soaps and detergents, charged colloidal particles, the Cottrell precipitator, and gels).
- Mechanisms of Microbial Genetics (Microbiology)Recall cards on the mechanisms of microbial genetics. The functions of genetic material and the stages of replication, transcription, and translation. DNA replication: semiconservative replication and the Meselson-Stahl experiment, the origin oriC, the replication enzymes (DNA polymerases III and I, helicase, primase, ligase, topoisomerases, single-stranded binding proteins, and the sliding clamp), leading and lagging strands, Okazaki fragments, replication rates, and telomeres and telomerase. RNA transcription: template and sense strands, bacterial RNA polymerase and the sigma factor, promoters and the TATA box, and the processing of eukaryotic pre-mRNA (5' cap, poly-A tail, and splicing of exons and introns). Protein synthesis: the genetic code and its degeneracy, codons and anticodons, transfer RNA and aminoacyl-tRNA synthetases, the prokaryotic and eukaryotic ribosomes, the A, P, and E sites, and initiation, elongation, and termination. Mutations: point, silent, missense, nonsense, and frameshift mutations, mutagens, DNA repair, and the Ames test. Horizontal gene transfer: transformation, transduction, and conjugation, transposons, and R plasmids. And gene regulation: operons, repressors and activators, and the lac and trp operons, attenuation, regulons, alarmones, and riboswitches.
- Circulatory and Lymphatic System Infections (Microbiology)Recall cards on the circulatory and lymphatic system infections of microbiology. Anatomy: the closed circulatory system and the four-chambered heart, the arteries, veins, and capillaries, the spleen and liver, and the lymphatic system with its lymph, lymph nodes, and primary and secondary lymphoid tissues. Signs and conditions: bacteremia, septicemia, viremia, toxemia, sepsis and SIRS, endocarditis, pericarditis, myocarditis, vasculitis, lymphangitis, and buboes. Bacterial infections: toxic shock syndromes, rheumatic fever, bacterial endocarditis, gas gangrene, tularemia, brucellosis, cat-scratch disease, plague, the tickborne rickettsial and ehrlichial diseases, the typhus fevers, Rocky Mountain spotted fever, Lyme disease, and relapsing fever. Viral infections: infectious mononucleosis and Burkitt lymphoma, cytomegalovirus, yellow fever, dengue, chikungunya, Ebola, the hantaviruses, and HIV and AIDS. And parasitic infections: malaria, toxoplasmosis, babesiosis, Chagas disease, leishmaniasis, and schistosomiasis.
- Microbial Metabolism (Microbiology)Recall cards on microbial metabolism. Energy, matter, and enzymes: anabolism and catabolism, autotrophs and heterotrophs, photo-, chemo-, organo-, and lithotrophs, redox reactions and the carriers NAD+, NADP+, and FAD, ATP structure and phosphorylation, and enzymes, activation energy, active sites, induced fit, cofactors and coenzymes, denaturation, and competitive, noncompetitive, and feedback inhibition. Catabolism of carbohydrates: glycolysis and its investment and payoff phases, substrate-level phosphorylation, the ED and pentose phosphate pathways, the transition reaction, and the Krebs cycle. Cellular respiration: the electron transport system, aerobic and anaerobic respiration, chemiosmosis and the proton motive force, ATP synthase, oxidative phosphorylation, and ATP yields. Fermentation: lactic acid, alcohol, and the industrial fermentations, plus identification tests. Catabolism of lipids and proteins: lipases, beta-oxidation, proteases, and deamination. Photosynthesis: light-dependent and light-independent reactions, thylakoids, photosystems and pigments, oxygenic and anoxygenic photosynthesis, the Z-scheme, and the Calvin cycle with RuBisCO. And the biogeochemical carbon, nitrogen, and sulfur cycles, plus bioremediation.
- Microbial Mechanisms of Pathogenicity (Microbiology)Recall cards on how pathogens cause disease. Characteristics of infectious disease: signs versus symptoms, normal vital-sign baselines, syndromes, the vocabulary of disease (communicable, contagious, iatrogenic, nosocomial, zoonotic, acute, chronic, latent), and the five periods of disease. How pathogens cause disease: Koch's postulates and their limitations, the molecular Koch's postulates, pathogenicity and virulence, ID50 and LD50, primary versus opportunistic pathogens, the stages of pathogenesis, portals of entry and exit, adhesion, invasion, and the types of infection. Virulence factors of bacterial and viral pathogens: adhesins, exoenzymes, endotoxin versus exotoxins, A-B and membrane-disrupting toxins, superantigens, capsules, and antigenic variation. And virulence factors of eukaryotic pathogens: fungal adhesins and mycotoxins, and protozoan and helminthic evasion strategies.
- InvertebratesRecall cards on the major invertebrate phyla: the tissue-less sponges (Porifera) with their spongocoel, choanocytes, and spicules; the diploblastic Cnidaria with their cnidocytes, polyp and medusa forms, and coral reefs; the lophotrochozoan flatworms, rotifers, and nemerteans; the mollusks and the segmented annelids; the molting ecdysozoan nematodes and tardigrades; the arthropods with their exoskeleton, tagmata, and subphyla from chelicerates to insects; and the invertebrate deuterostomes, the echinoderms with their water vascular system and the invertebrate chordates.
- BooksLiterature, famous authors, novels, and classic works
- Organic Chemistry (Chemistry)Recall cards on organic chemistry: the hydrocarbons (alkanes, alkenes, alkynes, and aromatic compounds), their bonding, hybridization, reactions (substitution and addition), isomerism (constitutional and geometric), and IUPAC naming; the oxygen-containing functional groups including alcohols and ethers; the carbonyl compounds aldehydes, ketones, carboxylic acids, and esters, their functional groups, nomenclature, oxidation and reduction relationships, and everyday examples; and the nitrogen-containing amines and amides, including amidation, peptide bonds, proteins, enzymes, and polyamides such as Kevlar.
- Urogenital System Infections (Microbiology)Recall cards on the urogenital system infections of microbiology. Anatomy and normal microbiota: the kidneys, nephrons, glomeruli, ureters, bladder, and urethra; the male and female reproductive structures; and the protective vaginal Lactobacillus microbiota with its lactic acid, glycogen, and estrogen-linked pH. Bacterial infections of the urinary system: UTIs, cystitis, pyelonephritis, and glomerulonephritis, their causes and dipstick diagnosis, plus leptospirosis, post-streptococcal glomerulonephritis, and nongonococcal urethritis. Bacterial infections of the reproductive system: gonorrhea, chlamydia, syphilis and its stages, chancroid, and bacterial vaginosis. Viral infections: genital herpes and human papillomavirus with its oncogenic types and vaccines. Fungal infections: vulvovaginal candidiasis. And the protozoan infection trichomoniasis.
- Plant Form and PhysiologyRecall cards on plant form and physiology: the shoot and root organ systems; meristematic and permanent tissues and the dermal, vascular, and ground tissue systems; stem anatomy and modifications, primary and secondary growth, wood, and bark; root structure and zones, the endodermis and Casparian strip, and root modifications; leaf anatomy, venation, phyllotaxy, and adaptations; water potential, transpiration and the cohesion-tension theory, and phloem translocation by the pressure-flow model; and plant sensory systems, from phytochrome and photoperiodism to the plant hormones and defenses.
- Diseases of the Immune System (Microbiology)Recall cards on diseases of the immune system. Hypersensitivities: the four types (I IgE and mast cells, II IgG/IgM against cell-surface antigens, III immune complexes, IV T-cell mediated), mast cell mediators, anaphylaxis, the ABO and Rh blood group systems, hemolytic transfusion reactions and hemolytic disease of the newborn, serum sickness, delayed-type hypersensitivity, hypersensitivity pneumonitis, skin testing, desensitization, and the hygiene hypothesis. Autoimmune disorders: loss of tolerance, antigenic mimicry, and specific diseases (celiac disease, Graves disease, Hashimoto thyroiditis, type 1 diabetes, Addison disease, multiple sclerosis, myasthenia gravis, psoriasis, rheumatoid arthritis, and systemic lupus erythematosus). Organ transplantation and rejection: autografts, isografts, allografts, and xenografts, human leukocyte antigens and HLA matching, the mechanism of rejection, immunosuppression, and graft-versus-host disease. Immunodeficiency: primary versus secondary, chronic granulomatous disease, X-linked agammaglobulinemia, selective IgA deficiency, and severe combined immunodeficiency. And cancer immunobiology: tumor antigens, the anti-tumor immune response, immune evasion, and preventive and therapeutic cancer vaccines and immunotherapies.
- The Cell (Microbiology)Recall cards on the cell. The fall of spontaneous generation: Aristotle and pneuma, van Helmont's mice, Redi's 1668 maggot experiment, Needham versus Spallanzani, and Pasteur's swan-neck flasks and Omne vivum ex vivo. Foundations of modern cell theory: biogenesis, Hooke's cork cells, Schleiden and Schwann, Remak and Virchow, the endosymbiotic theory of Mereschkowski and Margulis, and the germ theory of disease from Semmelweis and Snow to Lister and Koch. Unique characteristics of prokaryotic cells: cell shapes and arrangements, the nucleoid and plasmids, 70S ribosomes, inclusions and endospores, membranes and transport, peptidoglycan and Gram-positive versus Gram-negative walls, lipopolysaccharide, the glycocalyx, fimbriae and pili, and flagella and chemotaxis. Unique characteristics of eukaryotic cells: the nucleus and nucleolus, 80S ribosomes, the endomembrane system, lysosomes and peroxisomes, mitochondria and chloroplasts, the cytoskeleton and centrioles, cell walls and the extracellular matrix, the 9+2 flagellum, and mitosis and meiosis.
- Atoms, Molecules, and Ions (Chemistry)Recall cards on atoms, molecules, and ions: early ideas in atomic theory (Dalton's postulates; the laws of conservation of matter, definite proportions, and multiple proportions); the evolution of atomic theory (Thomson's cathode rays and the electron; Millikan's oil drop experiment; the plum pudding model; Rutherford's gold foil experiment and the nucleus; the proton, neutron, and isotopes); atomic structure and symbolism (the atomic mass unit; atomic number, mass number, and neutron count; isotope notation; ions, cations, and anions; average atomic mass); chemical formulas (molecular, empirical, and structural formulas; molecular models); the periodic table (the periodic law; periods and groups; metals, nonmetals, and metalloids; the element families); molecular and ionic compounds (ionic and covalent bonds; ion charges; monatomic and polyatomic ions); and chemical nomenclature (naming ionic compounds and the Stock system, binary molecular compounds, and acids).
- Liquids and Solids (Chemistry)Recall cards on the condensed phases of matter: intermolecular forces (the distinction from intramolecular forces, van der Waals forces, dispersion/London forces and polarizability, dipole-dipole attractions, and hydrogen bonding); the properties of liquids (viscosity, cohesion and adhesion, surface tension, and capillary action); phase transitions (vaporization and condensation, vapor pressure, boiling point, the Clausius-Clapeyron equation, melting and freezing, sublimation and deposition, and the associated enthalpies); phase diagrams (their axes and regions, the solid-liquid, liquid-gas, and solid-gas curves, the triple point, and the critical point); the solid state (crystalline versus amorphous solids and the four types of crystalline solid: ionic, metallic, covalent network, and molecular, plus crystal defects and doping); and lattice structures (the unit cell, simple cubic, body-centered cubic, and face-centered cubic structures with their coordination numbers and packing efficiencies, closest packing, tetrahedral and octahedral holes, the sodium chloride structure, and X-ray diffraction with the Bragg equation).
- Particle Physics and Cosmology (Physics)Recall cards on particle physics and cosmology. The four fundamental forces and their ranges and relative strengths. Fermions and bosons; the six quarks and their fractional charges; hadrons, mesons, and baryons; the six leptons; force carriers (photon, gluons, W and Z bosons, graviton) and the Higgs boson; antiparticles and annihilation. Conservation laws: baryon number, the three lepton numbers, strangeness, and neutrino oscillations. Quarks: spin, color charge, confinement, gluons, and the deep-inelastic-scattering evidence. Particle accelerators (Van de Graaff, linac, cyclotron, synchrotron, colliding beams, the LHC) and detectors. The Standard Model: electroweak theory, quantum electrodynamics, quantum chromodynamics, Feynman diagrams, virtual particles, and grand unified theories. Cosmology: Hubble's law, the Hubble constant, the Big Bang as expanding space, cosmological redshift, the age of the universe, the epochs of the early universe, Big Bang nucleosynthesis, the cosmic microwave background, and dark energy and dark matter.
- Chemical ElementsLearn the periodic table - match symbols to element names
- The Animal Body: Basic Form and FunctionRecall cards on animal form and function: body symmetry and directional terms; the physical constraints of size and shape (drag, gravity, exoskeletons, endoskeletons, diffusion and the surface-area-to-volume ratio); animal bioenergetics (energy storage, metabolic rate, endotherms and ectotherms, torpor); anatomical planes and body cavities; the four primary tissues (epithelial, connective, muscle, and nervous); and homeostasis (set points, negative and positive feedback, acclimatization, and thermoregulation).
- Adaptive Specific Host Defenses (Microbiology)Recall cards on the adaptive, specific host defenses. Overview of specific adaptive immunity: specificity and memory, primary and secondary responses, humoral versus cell-mediated immunity, antigens and epitopes, haptens, and the five antibody classes (IgG, IgM, IgA, IgD, IgE) with their structures and functions. Major histocompatibility complexes and antigen-presenting cells: MHC class I and class II, antigen processing, and cross-presentation. T lymphocytes and cellular immunity: thymic selection and tolerance, T-cell receptors, CD4 helper and CD8 cytotoxic T cells, perforin and granzymes, and superantigens. B lymphocytes and humoral immunity: B-cell receptors, T-dependent and T-independent activation, plasma cells, class switching, memory B cells, and the kinetics of the primary and secondary antibody responses. And vaccines: variolation and Jenner, herd immunity, and the live attenuated, inactivated, subunit, toxoid, conjugate, and DNA vaccine types.
- Electrochemistry (Chemistry)Recall cards on electrochemistry: a review of redox chemistry (oxidation numbers and their rules, oxidants and reductants, and the half-reaction method for balancing redox equations); galvanic cells (half-cells, anode and cathode, salt bridges, active and inert electrodes, and cell notation); electrode and cell potentials (the volt, standard cell potential, the standard hydrogen electrode, tabulated standard reduction potentials, and predicting spontaneity); the links among potential, free energy, and equilibrium (delta-G = -nFE, Faraday's constant, the relationship of E-degree-cell to K, and the Nernst equation); batteries and fuel cells (primary and secondary cells, the dry, alkaline, NiCd, lithium-ion, and lead-acid batteries, and the hydrogen fuel cell); corrosion (the electrochemistry of rusting and methods of protection such as galvanization, passivation, and sacrificial anodes); and electrolysis (electrolytic cells, overpotential, the Downs and chlor-alkali processes, and the stoichiometry relating charge to amount of substance produced).
- Innate Nonspecific Host Defenses (Microbiology)Recall cards on the innate, nonspecific defenses of the host. Physical defenses: the skin and its layers, cell junctions, mucous membranes and the mucociliary escalator, flushing actions, and competitive exclusion by the resident microbiota. Chemical defenses: sebum and acidity, lysozyme and iron-binding proteins, antimicrobial peptides, acute-phase proteins, the complement system and its three activation pathways, cytokines, interferons, and inflammatory mediators. Cellular defenses: the formed elements of blood, granulocytes and agranulocytes, macrophages and dendritic cells, and natural killer cells. Pathogen recognition and phagocytosis: PAMPs and pattern recognition receptors, the phagosome and phagolysosome, and oxygen-dependent and oxygen-independent killing. And inflammation and fever: the signs of inflammation, pus and granulomas, pyrogens, and the resetting of the hypothalamic thermostat.
- Antimicrobial Drugs (Microbiology)Recall cards on antimicrobial drugs. The history of chemotherapy and antimicrobial discovery: Ehrlich's Salvarsan, prontosil, Fleming's penicillin, Florey and Chain, Waksman, and the actinomycetes. The fundamentals of antimicrobial chemotherapy: bacteriostatic versus bactericidal drugs, narrow versus broad spectrum, superinfections, half-lives, dose- versus time-dependent killing, and synergy. Mechanisms of antibacterial drugs by target: cell wall synthesis (beta-lactams, vancomycin, bacitracin), protein synthesis (aminoglycosides, tetracyclines, macrolides, lincosamides, chloramphenicol, oxazolidinones), nucleic acid synthesis (rifampin, fluoroquinolones), metabolic pathways (sulfonamides, trimethoprim, isoniazid), and the cell membrane (polymyxins, daptomycin). Mechanisms of antifungal, antiprotozoan, anthelmintic, and antiviral drugs. Drug resistance mechanisms and the major resistant pathogens (MRSA, VRSA, VRE, ESBLs, CRE, MDR-TB, XDR-TB). Testing effectiveness: the Kirby-Bauer disk diffusion test, MIC, MBC, and the Etest. And current strategies for antimicrobial discovery, including high-throughput screening, the iChip, and teixobactin.
- Animal Reproduction and DevelopmentRecall cards on how animals reproduce and develop: asexual modes (fission, budding, fragmentation, and parthenogenesis) versus sexual reproduction, hermaphroditism, and the genetic, chromosomal, and environmental systems of sex determination; fertilization strategies (external broadcast spawning versus internal fertilization, and oviparity, ovoviviparity, and viviparity); human reproductive anatomy and gametogenesis (the male and female organs, semen and the accessory glands, and spermatogenesis and oogenesis by meiosis); the hormonal control of reproduction (the hypothalamic-pituitary-gonadal axis, testosterone, estradiol and progesterone, the ovarian and menstrual cycles, and menopause); human pregnancy and birth (implantation and beta-HCG, the placenta, the three trimesters, labor and lactation, contraception, infertility, and assisted reproduction); early embryonic development (fertilization and blocks to polyspermy, cleavage, the blastula and blastocyst, and gastrulation into the three germ layers); and organogenesis and vertebrate body formation (neural tube, somites, notochord, body axes, and left-right asymmetry).
- Skin and Eye Infections (Microbiology)Recall cards on the skin and eye infections of microbiology. Anatomy and normal microbiota: the epidermis, dermis, and hypodermis, the stratum corneum and keratin, desquamation, sweat and sebaceous glands, resident bacteria and fungi by skin region, and the conjunctiva, lacrimal gland, and tears. Bacterial infections: Staphylococcus aureus virulence factors, folliculitis, furuncles and carbuncles, scalded skin syndrome, MRSA, Streptococcus pyogenes, cellulitis, erysipelas, necrotizing fasciitis, impetigo, acne and Cutibacterium acnes, Pseudomonas infections, cutaneous and inhalation anthrax, and the bacterial eye infections including conjunctivitis, ophthalmia neonatorum, trachoma, and keratitis. Viral infections: warts and HPV, oral herpes and HSV-1, roseola, fifth disease, and viral conjunctivitis. Mycoses: cutaneous and subcutaneous mycoses, the tineas (ringworm), aspergillosis, candidiasis, sporotrichosis, and fungal diagnosis with the Wood's lamp, KOH prep, and Sabouraud dextrose agar. And protozoan and helminthic infections: Acanthamoeba keratitis and the Loa loa eye worm.
- The Immune SystemRecall cards on how animals defend against pathogens: the innate immune response (physical and chemical barriers, PAMPs and pattern recognition receptors including Toll-like receptors, phagocytes such as macrophages and neutrophils, cytokines, interferons and inflammation, natural killer cells and MHC I recognition, and the complement cascade); the adaptive immune response (cell-mediated versus humoral immunity, antigen-presenting cells and MHC processing, helper and cytotoxic T cells, T cell receptors, B cells and clonal selection, immune tolerance, immunological memory and vaccination, mucosal immunity, and the lymphatic organs); antibodies (their four-chain structure and gene recombination, the five immunoglobulin classes, neutralization, opsonization and complement fixation, affinity and avidity, cross reactivity, and radioimmunoassay); and disruptions of immunity (immunodeficiency, immediate and delayed hypersensitivity and allergy, autoimmunity, and pathogen evasion strategies).
- The Nervous SystemRecall cards on the animal nervous system: neuron structure (soma, dendrites, axon, synapse) and the neuron types; glial cells (astrocytes, microglia, oligodendrocytes, Schwann cells, and others); how neurons communicate through the resting membrane potential, the action potential, and chemical and electrical synapses; synaptic integration and plasticity (summation, LTP, LTD); the central nervous system (meninges, cerebrospinal fluid, the cortex and its lobes, subcortical structures, the brainstem, and the spinal cord); the peripheral nervous system (autonomic sympathetic and parasympathetic divisions and the sensory-somatic division); and nervous system disorders (Alzheimer's, Parkinson's, autism, ADHD, schizophrenia, depression, epilepsy, and stroke).
- Biopsychology (Psychology)Recall cards on the biological bases of behavior. Human genetics: genotype and phenotype, chromosomes and DNA, genes and alleles, dominant and recessive traits, homozygous and heterozygous, polygenic traits, mutations, PKU, range of reaction, epigenetics, natural selection, and twin studies. Cells of the nervous system: neurons and glial cells, soma, dendrites, axon, myelin sheath, nodes of Ranvier, the synapse, neurotransmitters and receptors, membrane and resting potential, the action potential and the all-or-none phenomenon, the sodium-potassium pump, reuptake, agonists and antagonists, and the major neurotransmitters. Parts of the nervous system: the central, somatic, autonomic, sympathetic, and parasympathetic divisions, afferent and efferent fibers, and homeostasis. The brain and spinal cord: the cerebral cortex, hemispheres and lateralization, the four lobes, motor and somatosensory cortex, Broca's and Wernicke's areas, the limbic system, subcortical structures, split-brain and neuroplasticity, and brain-imaging methods. And the endocrine system: glands and hormones, the pituitary master gland, thyroid, adrenal glands, pancreas, and gonads.
- Advanced Theories of Covalent Bonding (Chemistry)Recall cards on advanced covalent bonding theory: valence bond theory (the overlap of half-filled atomic orbitals, orbital overlap and bond strength, the energy of bond formation and bond distance, and sigma and pi bonds in single, double, and triple bonds); hybrid atomic orbitals (hybridization and its relation to VSEPR electron-pair geometry, and the sp, sp2, sp3, sp3d, and sp3d2 hybrid sets with their geometries and bond angles); multiple bonds (the sigma-plus-pi description of double and triple bonds in ethene and acetylene, restricted rotation about double bonds, and delocalization in benzene); and molecular orbital theory (bonding and antibonding molecular orbitals from the linear combination of atomic orbitals, molecular orbital diagrams, bond order, paramagnetism and diamagnetism, the paramagnetism of oxygen, and s-p mixing in second-period diatomic molecules).
- Osmotic Regulation and ExcretionRecall cards on how animals balance water and salts and clear nitrogenous waste: osmoregulation and osmotic balance (osmosis, electrolytes and non-electrolytes, tonicity, the ways concentration is measured, and stenohaline versus euryhaline strategies in fish, osmoconformers, and sharks); the kidneys and osmoregulatory organs (gross kidney anatomy, the nephron and its blood supply, and the three steps of urine formation including the loop of Henle countercurrent system and the juxtaglomerular complex); excretion systems of invertebrates (contractile vacuoles, flame cells, nephridia, and Malpighian tubules); nitrogenous wastes (ammonotelic, ureotelic, and uricotelic animals, the urea cycle, and uric acid, gout, and kidney stones); and the hormonal control of osmoregulation (the renin-angiotensin-aldosterone system, aldosterone, antidiuretic hormone, and atrial natriuretic peptide).
- Psychological Disorders (Psychology)Recall cards on psychological disorders. Defining and classifying disorders: what a psychological disorder is, psychopathology, etiology, Wakefield's harmful dysfunction model, cultural relativism, Szasz's critique, diagnosis, the DSM-5 and ICD, and comorbidity. Perspectives: supernatural, biological, and psychological views, the diathesis-stress model, and the biopsychosocial model. Anxiety disorders: generalized anxiety disorder, panic attacks and panic disorder, the locus coeruleus, agoraphobia, specific and social phobias, prepared learning, behavioral inhibition, and safety behaviors. Obsessive-compulsive and related disorders: obsessions, compulsions, OCD, body dysmorphic disorder, and hoarding. Posttraumatic stress disorder: its criteria, intrusion, avoidance, and arousal symptoms. Mood disorders: major depressive disorder, persistent depressive disorder, bipolar disorder and manic episodes, the monoamine hypothesis, Beck's cognitive theory, hopelessness theory, rumination, and suicide. Schizophrenia: hallucinations, delusions, disorganized thinking, negative symptoms, the dopamine hypothesis, and brain abnormalities. Dissociative disorders, disorders in childhood (ADHD and autism spectrum disorder), and personality disorders (Clusters A, B, and C).
- The Circulatory SystemRecall cards on the animal circulatory system: an overview of circulation (why bulk flow replaces diffusion as body size grows, open versus closed systems, and the evolution of two-, three-, and four-chambered hearts across fish, amphibians, reptiles, birds, and mammals); the components of the blood (plasma, red blood cells and hemoglobin, alternative respiratory pigments, white blood cells, platelets and clotting, serum proteins, and the ABO and Rh blood groups); the mammalian heart and blood vessels (the chambers, valves, wall layers and coronary supply, the cardiac cycle and its conduction system from the SA node to the Purkinje fibers, and the structure of arteries, capillaries, and veins); and blood flow and blood pressure regulation (systolic and diastolic pressure, flow speed and capillary exchange, precapillary sphincters, the lymphatic system, and cardiac output).
- Nuclear Chemistry (Chemistry)Recall cards on nuclear chemistry: nuclear structure and stability (nucleons, atomic and mass numbers, isotopes, the strong force, mass defect and binding energy, the band of stability, and magic numbers); writing and balancing nuclear equations with alpha, beta, positron, and gamma particles; radioactive decay (alpha, beta, gamma, positron emission, and electron capture, half-life, first-order kinetics, and radiometric dating); transmutation and nuclear energy (particle accelerators, transuranium elements, fission, chain reactions, reactor design, and fusion); uses of radioisotopes (medical tracers, therapy, and smoke detectors); and the biological effects of radiation (ionizing versus nonionizing radiation, penetrating power and shielding, the units becquerel, curie, gray, rad, sievert, and rem, relative biological effectiveness, radon, dose limits, and detectors).
- Rings, Moons, and Pluto (Astronomy)Recall cards on the moon and ring systems of the giant planets, and on the dwarf planet Pluto. The four Galilean moons of Jupiter: heavily cratered Callisto, giant Ganymede, ocean-bearing Europa, and volcanic Io, whose eruptions are driven by tidal heating. Saturn's moons, including Titan with its thick nitrogen atmosphere and hydrocarbon lakes, and Enceladus with its water geysers and subsurface ocean. Neptune's captured moon Triton, the coldest world yet visited, with its nitrogen geysers. Pluto and its large moon Charon, in a double tidal lock, explored by New Horizons in 2015. And the planetary ring systems: the bright, broad water-ice rings of Saturn with the Cassini Division, the dark narrow rings of Uranus and Neptune, and how orbital resonances and shepherd moons sculpt them.
- Modern Applications of Microbial Genetics (Microbiology)Recall cards on the modern applications of microbial genetics. The tools of genetic engineering: recombinant DNA and molecular cloning, restriction enzymes and sticky versus blunt ends, DNA ligase, plasmid vectors, the multiple cloning site, selectable markers, pUC19 and blue-white screening, transformation and competence, F plasmids and phagemids, genomic and cDNA libraries, transfection methods (electroporation, microinjection, gene guns), shuttle vectors, the Ti plasmid, and viral vectors. Visualizing and characterizing DNA, RNA, and protein: agarose gel electrophoresis, ethidium bromide, pulsed-field gels, RFLP, DNA probes and hybridization, Southern, Northern, and colony blots, microarrays, the polymerase chain reaction and its denaturation, annealing, and extension steps, Taq polymerase, RT-PCR and qPCR, Sanger and next-generation sequencing, GenBank, PAGE and SDS-PAGE, and NAATs, ribotyping, and rep-PCR. Whole genome methods: transcriptomics, proteomics, metagenomics, pharmacogenomics, and metabolomics, reverse genetics, reporter genes, and biomarkers, plus pharmaceutical applications (recombinant insulin, growth hormone, Factor VIII, and tPA, subunit vaccines, and RNA interference with siRNA, miRNA, Dicer, and RISC). And gene therapy: adenovirus vectors, SCID and adenosine deaminase deficiency, the death of Jesse Gelsinger, insertional mutagenesis, somatic versus germline therapy, and regulation.
- Earth, Moon, and Sky (Astronomy)Recall cards on how Earth's motions define the sky and our measures of time. The celestial sphere: great circles, meridians, longitude and latitude, the celestial equator and poles, declination and right ascension, and Foucault's pendulum. The seasons: Earth's 23.5-degree axial tilt, solstices and equinoxes, and the tropics and polar circles. Keeping time: sidereal versus solar days, apparent and mean solar time, standard time zones, daylight saving, and the International Date Line. The calendar: the tropical year and synodic month, the Julian and Gregorian reforms, and leap-year rules. Phases and motions of the Moon: the sidereal and synodic months, phase rise and set times, and synchronous rotation. Ocean tides: the tidal force, two bulges, spring and neap tides, and tidal friction. Finally eclipses of the Sun and Moon: umbra and penumbra, annular and total eclipses, and why they do not happen every month.
- Acellular Pathogens (Microbiology)Recall cards on the acellular pathogens. Viruses: virions, capsids and capsomeres, naked versus enveloped particles, glycoprotein spikes, size range, and the helical, polyhedral, and complex morphologies; DNA and RNA genomes, host range, ICTV taxonomy and the Baltimore classification, and the history from Ivanovski to Beijerinck to Stanley. The viral life cycle: the bacteriophage lytic cycle, temperate phages and lysogeny (prophage, lysogen, lysogenic conversion, induction, lambda), generalized and specialized transduction, the animal virus cycle with endocytosis, budding, and tissue tropism, positive- and negative-strand RNA and RNA-dependent RNA polymerase, retroviruses and proviruses (HIV), and latent and chronic infections (varicella-zoster, hepatitis C). Isolation, culture, and identification: in vivo and in vitro cultivation, embryonated eggs, primary and continuous cell lines (HeLa, contact inhibition), cytopathic effects (syncytia, inclusion bodies), plaque assays, hemagglutination and hemagglutination inhibition, RT-PCR, and enzyme immunoassays. And the subviral agents: viroids (Diener, PSTVd, ASBVd), virusoids and satellite RNAs (HDV), and prions (Prusiner, PrPc versus PrPsc, TSEs, CJD, kuru, mad cow, scrapie, and chronic wasting disease).
- Kinetics (Chemistry)Recall cards on chemical kinetics: reaction rates (average, instantaneous, and initial rates, the sign convention, rates from the tangent to a concentration-versus-time curve, and stoichiometric rate relations); the factors that affect rates (chemical nature, physical state and surface area, temperature, concentration, and catalysts); rate laws (the rate constant, reaction order, the method of initial rates, and the units of k); integrated rate laws (the first-, second-, and zero-order equations, their linear plots, and their half-lives); collision theory (activation energy, the activated complex, and the Arrhenius equation with its linear form and plot); reaction mechanisms (elementary reactions, intermediates, molecularity, and the rate-determining step); and catalysis (lower-activation-energy pathways, homogeneous versus heterogeneous catalysts, and enzymes).
- Prokaryotic Diversity (Microbiology)Recall cards on prokaryotic diversity. Prokaryote habitats, relationships, and microbiomes: extreme habitats, nitrogen fixation and Rhizobium, the symbiotic relationships (mutualism, commensalism, amensalism, parasitism, neutralism), resident and transient microbiota, and the Human Microbiome Project. Proteobacteria: Woese's 1987 phylum and its five classes, Rickettsia, Pseudomonas, Vibrio, Legionella, Neisseria, Bordetella, Bdellovibrio, myxobacteria, Campylobacter, and Helicobacter. Nonproteobacteria gram-negatives and phototrophs: spirochetes (Treponema, Borrelia), the CFB group and Bacteroides, Planctomycetes, and oxygenic versus anoxygenic photosynthesis in purple and green sulfur bacteria and cyanobacteria. Gram-positive bacteria: high versus low G+C, Mycobacterium, Corynebacterium, Streptomyces, Clostridium, Streptococcus, Staphylococcus, Bacillus, Lactobacillus, and Mycoplasma. Deeply branching bacteria near the last universal common ancestor: Acetothermus, Aquifex, Thermotoga, and Deinococcus. And the domain Archaea: ether-linked membranes, no peptidoglycan, methanogenesis, the five phyla, and extremophiles from Sulfolobus to Halobacteria.
- The Solar System: An Overview (Astronomy)Recall cards introducing the solar system as a whole. Its inventory: the Sun, the eight planets, their moons and rings, and debris such as asteroids, comets, and dust, formed together about 4.5 billion years ago. The layout: the Sun holding 99.8 percent of the mass, the terrestrial versus jovian planets, distances in astronomical units and orbital periods, densities, and rotations. The smaller bodies: trans-Neptunian objects, the five dwarf planets, moons from the Galilean satellites to Titan and Triton, ring systems, asteroids, comets, meteors, and meteorites. Composition and structure: the hydrogen-rich giants, silicate-and-iron terrestrials, differentiation, and how surface temperature falls with distance. Dating surfaces by crater counts and by radioactive decay, with the major parent-daughter isotope pairs and their half-lives. And the origin of the solar system from a spinning solar nebula of gas and dust.
- The Eukaryotes of Microbiology (Microbiology)Recall cards on the eukaryotic microbes. Unicellular eukaryotic parasites: protozoan structure (trophozoite, cyst, ectoplasm and endoplasm, cytostome, cytoproct, contractile vacuoles, pseudopodia), reproduction (schizogony, merozoites, syngamy), the six eukaryotic supergroups, and named parasites from Entamoeba, Acanthamoeba, and Naegleria to Plasmodium, Toxoplasma, Giardia, Trichomonas, Trypanosoma, and Leishmania, plus ciliates and oomycetes. Parasitic helminths: roundworms of Nematoda (Ascaris, Enterobius, Toxocara, hookworms, Trichinella, heartworm) and flatworms of Platyhelminthes, both the trematode flukes (Schistosoma) and the cestode tapeworms (Taenia, Diphyllobothrium, Echinococcus), plus the Guinea worm. Fungi: chitin cell walls, ergosterols, hyphae and mycelia, yeasts, dimorphism, sexual reproduction (plasmogamy and karyogamy), the spore-defined phyla, and mycoses from dermatophytes and Candida to Coccidioides, Cryptococcus, and Amanita. Algae: autotrophic protists, oxygen production, dinoflagellates, diatoms, and the brown, green, and red seaweeds. And lichens: the fungus-photobiont symbiosis, the thallus, the three growth forms, and their role as air-quality indicators.
- VirusesRecall cards on viruses: their evolution, morphology, and classification (how viruses were discovered, their sizes and imaging, hypotheses for their origins, virion structure and capsid types, attachment and receptors, DNA versus RNA genomes, and the Baltimore classification groups); virus infections and hosts (the replication cycle, bacteriophage lytic and lysogenic cycles, animal and retrovirus replication, latency, viral release, acute, chronic, and asymptomatic infections, plant viruses and their transmission, and oncogenic viruses); prevention and treatment (vaccines, antiviral drugs, HIV therapy, and viruses and phages used in medicine); and other acellular entities (prions and viroids).
- Ecology and the BiosphereRecall cards on ecology and the biosphere: the scope of ecology and its four levels of organization (organism, population, community, and ecosystem), species interactions, and mutualism; biogeography, endemic versus generalist species, and the abiotic factors (light, temperature, water, inorganic nutrients, oxygen, wind, and fire) that shape where organisms live, including lake turnover, upwelling, migration, torpor, and net primary productivity; the terrestrial biomes (tropical wet forest, savanna, subtropical desert, chaparral, temperate grassland, temperate forest, boreal forest, and Arctic tundra) with their climate, vegetation, and soils; the aquatic biomes (ocean zones, coral reefs and bleaching, estuaries, lakes and ponds, rivers and streams, and wetlands); and climate versus weather, the ice-core record, Milankovitch cycles, the greenhouse effect and greenhouse gases, the rise in atmospheric carbon dioxide, methane and clathrate feedback, glacier and ice loss, sea-level rise, and phenology shifts.
- The Musculoskeletal SystemRecall cards on the animal musculoskeletal system: the three skeletal designs (hydrostatic skeleton, exoskeleton, endoskeleton) and the 206-bone human axial and appendicular skeleton (skull, vertebral column, thoracic cage, girdles, and limbs); bone as a tissue (bone shapes, compact and spongy bone, osteons, the four bone cell types, ossification, growth, remodeling, and fracture repair); the structural and functional classification of joints (fibrous, cartilaginous, and the six synovial joint types) and the body movements they allow; and muscle contraction (the three muscle tissue types, sarcomere and myofilament structure, the sliding filament model, the cross-bridge and ATP cycle, excitation-contraction coupling at the neuromuscular junction, and how muscle tension and whole-muscle force are set).
- Greek MythologyAncient Greek gods, heroes, monsters, and legends
- Microbial Growth (Microbiology)Recall cards on microbial growth. How microbes grow: binary fission, the FtsZ Z ring and the divisome, generation (doubling) time, exponential growth and the growth curve (lag, log, stationary, and death phases), persister cells, budding and multiple fission, biofilms and extracellular polymeric substances, and quorum sensing. Counting microbes: viable plate counts and colony-forming units, serial dilution, pour and spread plates, membrane filtration, the most probable number method, direct counts with a Petroff-Hausser chamber or Coulter counter, turbidity, and dry weight. Oxygen requirements: obligate aerobes and anaerobes, facultative and aerotolerant anaerobes, microaerophiles and capnophiles, reactive oxygen species, and the detoxifying enzymes superoxide dismutase, catalase, and peroxidase. The effects of pH: acidophiles, neutrophiles, and alkaliphiles. Temperature: cardinal temperatures and the psychrophile through hyperthermophile classes, plus Taq polymerase and heat and cold adaptations. Other conditions: osmotic pressure and plasmolysis, halophiles and halotolerance, water activity, and barophiles. And the media used for bacterial growth: chemically defined, complex, selective, differential, and enrichment media.
- Acid-Base Equilibria (Chemistry)Recall cards on aqueous acid-base equilibria: the Bronsted-Lowry model (proton donors and acceptors, conjugate acid-base pairs, amphiprotic species, and the autoionization of water with its ion-product constant Kw); the pH and pOH scales (their definitions, the 25 C relation pH + pOH = 14, and acidic, neutral, and basic ranges); relative acid and base strengths (strong versus weak, Ka and Kb, percent ionization, the Ka x Kb = Kw relation for a conjugate pair, the leveling effect, and molecular-structure trends in binary and oxyacids); salt hydrolysis and the acidity of hydrated metal ions; polyprotic acids and their successive ionization constants; buffers (composition, action, capacity, and the Henderson-Hasselbalch equation); and acid-base titrations (titration curves, equivalence and end points, and indicator choice).
- Personality (Psychology)Recall cards on personality: the long-standing traits and patterns that shape how we think, feel, and behave. History: the Latin persona, Hippocrates's four humors and temperaments, Galen, and Gall's phrenology. Freud's psychodynamic perspective: the unconscious, the id, ego, and superego, the pleasure and reality principles, the defense mechanisms (repression, denial, regression, projection, reaction formation, displacement, rationalization, and sublimation), the five psychosexual stages, fixation, and the Oedipus complex. The neo-Freudians: Adler's inferiority complex and birth order, Erikson's psychosocial stages, Jung's collective unconscious, archetypes, and introversion-extroversion, and Horney's coping styles and womb envy. Learning approaches: Skinner, Bandura's social-cognitive theory and reciprocal determinism, Rotter's locus of control, and Mischel. Humanistic approaches: Maslow's deficit and growth needs and Rogers's self-concept, ideal and real self, congruence, and unconditional positive regard. Biological approaches: heritability, the Minnesota twin study, and temperament. Trait theorists: Allport, Cattell's 16PF, the Eysencks, and the Big Five (OCEAN). Cultural understandings: individualist and collectivist cultures and the three cross-cultural approaches. Personality assessment: self-report inventories, Likert scales, the MMPI, and the projective tests (Rorschach, TAT, RISB, C-TCB, and TEMAS).
- Radiation and Spectra (Astronomy)Recall cards on light and how it reveals the nature of matter across the universe. The behavior of light: Maxwell's electromagnetic theory, wavelength and frequency, the speed of light, the photon and wave-particle duality, and the inverse square law of brightness. The electromagnetic spectrum: gamma rays, X-rays, ultraviolet, visible, infrared, microwaves, and radio waves, plus Wien's law and the Stefan-Boltzmann law for blackbody radiation. Spectroscopy: Newton's prism, dispersion, continuous, absorption, and emission spectra, Fraunhofer lines, and Kirchhoff's identification of elements. The structure of the atom: electrons, protons, and neutrons, the nucleus, isotopes, the Bohr model, and Planck's constant. Formation of spectral lines: ground and excited states, excitation and emission, the Lyman, Balmer, and Paschen series of hydrogen, ionization, and recombination. Finally the Doppler effect: blueshift and redshift, radial velocity, and the Doppler formula.
- Sensation and Perception (Psychology)Recall cards on how we sense and perceive the world. Sensation versus perception: sensory receptors and transduction, absolute and difference thresholds, Weber's law, subliminal messages, bottom-up and top-down processing, sensory adaptation, inattentional blindness, and signal detection theory. Waves and wavelengths: amplitude, wavelength, and frequency, the visible spectrum, hue and brightness, pitch, loudness, the decibel, and timbre. Vision: the cornea, pupil, iris, lens, accommodation, retina, rods and cones, the fovea, optic nerve, blind spot, and optic chiasm, the trichromatic and opponent-process theories, afterimages, color blindness, and depth cues (binocular disparity, monocular cues, linear perspective). Hearing: audition, the pinna, eardrum, ossicles, cochlea, basilar membrane, and hair cells, temporal and place theories of pitch, sound localization, and conductive versus sensorineural hearing loss. The other senses: the chemical senses, the five tastes and umami, olfaction, pheromones, touch receptors, thermoception and nociception, and the vestibular sense, proprioception, and kinesthesia. And the Gestalt principles of perception: figure-ground, proximity, similarity, continuity, closure, and perceptual set.
- Comets and Asteroids (Astronomy)Recall cards on the small bodies of the solar system: asteroids and comets. The asteroid belt between Mars and Jupiter, the largest asteroids Ceres, Pallas, and Vesta, and the C-type, S-type, and M-type compositional classes. The spacecraft that visited and sampled asteroids: Galileo, NEAR-Shoemaker, Hayabusa, OSIRIS-REx, Dawn, and Lucy, plus the interstellar visitor 'Oumuamua. Near-Earth objects and planetary defense: the Tunguska and Chelyabinsk airbursts, the Spaceguard Survey, and the DART and Hera missions. The anatomy of a comet, its nucleus, coma, and tails, Fred Whipple's dirty snowball model, and famous comets such as Halley and 67P Churyumov-Gerasimenko explored by Rosetta and Philae. And the reservoirs that supply comets: the distant Oort cloud of long-period comets and the Kuiper belt beyond Neptune that feeds the short-period comets.
- The Giant Planets (Astronomy)Recall cards on the four giant planets of the outer solar system: Jupiter, Saturn, Uranus, and Neptune. The composition of the outer solar system and the distinction between the gas giants (Jupiter and Saturn) and the ice giants (Uranus and Neptune). The robotic missions that explored them: the Pioneers, the two Voyagers and their Grand Tour, Galileo and its atmospheric probe at Jupiter, Cassini and the Titan landing at Saturn, and Juno's polar orbit. The bulk properties of each planet: orbital period, diameter, mass, density, rotation, and axial tilt, including Uranus tipped on its side. Their interiors of liquid metallic hydrogen, rock-and-ice cores, internal heat sources, and strong tilted magnetic fields. And their atmospheres: the hydrogen-helium composition, the ammonia and methane cloud decks, the belts and zones, the ferocious jet streams, and the long-lived storms such as Jupiter's Great Red Spot and Neptune's Great Dark Spot.
- Gases (Chemistry)Recall cards on the behavior of gases: gas pressure (its definition as force per area, its origin in molecular collisions, the pascal, atmosphere, torr, mm Hg, bar, and psi units and their conversions, barometers and manometers, and hydrostatic pressure); the simple gas laws (Amontons's/Gay-Lussac's, Charles's, Boyle's, and Avogadro's laws with their equations) and the ideal gas law PV = nRT with the gas constant, standard temperature and pressure, the standard molar volume, the combined gas law, and absolute zero; gas stoichiometry (gas density and molar mass from the ideal gas law, the law of combining volumes, Dalton's law of partial pressures, mole fraction, and collecting a gas over water); effusion and diffusion (mean free path, Graham's law, and uranium enrichment); the kinetic-molecular theory (its postulates, molecular kinetic energy, root-mean-square speed, and the Maxwell-Boltzmann distribution); and non-ideal gas behavior (deviations at high pressure and low temperature, the compressibility factor, and the van der Waals equation).
- Waves (Physics)Recall cards on traveling and standing waves. Mechanical waves in a medium versus electromagnetic and matter waves. Amplitude, wavelength, period, and frequency, and the wave-speed relations v = lambda/T = lambda*f. Transverse versus longitudinal (compressional) waves. The mathematics of waves: the sinusoidal wave function y = A sin(kx - omega t + phi), wave number k = 2 pi/lambda, angular frequency omega = 2 pi/T, the phase and phase constant, transverse velocity and acceleration of a medium element, and the linear wave equation. Wave speed on a stretched string v = sqrt(F_T/mu) and the general elastic-over-inertial form. Energy and power of a wave: P = (1/2) mu A^2 omega^2 v, the amplitude-squared and frequency-squared scaling, intensity I = P/A, and the inverse-square law for a point source. Interference and superposition: constructive and destructive interference and the resultant amplitude 2A cos(phi/2). Standing waves and resonance: nodes and antinodes, the standing-wave function y = 2A sin(kx) cos(omega t), allowed wavelengths lambda_n = 2L/n and resonant frequencies f_n = n f_1 on a string fixed at both ends, harmonics, overtones, normal modes, and resonance.
- Control of Microbial Growth (Microbiology)Recall cards on the control of microbial growth. Terminology and the physical control of microbes: sterilization, disinfection, antisepsis, degerming, sanitization, asepsis, and sepsis; the -cide versus -stat suffixes; the microbial death curve and decimal reduction time (D-value); the factors that determine an antimicrobial protocol's effectiveness; and physical methods with their exact figures, the autoclave (121 degrees Celsius, 15 to 20 psi), HTST and UHT pasteurization, boiling, dry heat, thermal death point and time, refrigeration, freezing, lyophilization, high-pressure processing, HEPA and membrane filtration, and ionizing and ultraviolet radiation. Chemical control: phenolics, heavy metals and oligodynamic action, halogens, alcohols, surfactants and quaternary ammonium compounds, bisbiguanides, alkylating agents, peroxygens, and chemical food preservatives, each with its mechanism, examples, and limitations. And measuring effectiveness: the phenol coefficient, the disk-diffusion method, the use-dilution test, and the in-use test.
- Gravitation (Physics)Recall cards on Newtonian gravity and its consequences. Newton's law of universal gravitation gives an attractive, inverse-square force F = G m1 m2 / r^2 along the line joining two masses, with the universal constant G first measured by Cavendish; spherically symmetric bodies act as though their mass sits at the center, and net forces add by superposition. Gravitation near Earth's surface: g = GM/r^2, weight W = mg, the fall of all masses at the same rate, and the small corrections from altitude, Earth's rotation, and its equatorial bulge. Gravitational potential energy U = -GMm/r (zero at infinity), conservation of total mechanical energy, escape velocity sqrt(2GM/R), and gravitational binding. Satellite orbits: circular orbital speed and period, orbital energy E = -GMm/2r, geostationary orbits, and weightlessness in free fall. Kepler's three laws of planetary motion (ellipses, equal areas, and the period-axis relation) and their basis in angular momentum and the inverse-square force. Tidal forces, spring and neap tides, tidal locking, and Io's heating. Finally Einstein's theory of gravity: the equivalence principle, spacetime curvature, the Schwarzschild radius and black holes, gravitational lensing, and time dilation.
- Psychological Research (Psychology)Recall cards on how psychologists do research. Why research matters: evidence-based knowledge, theories and hypotheses, empirical evidence, facts versus opinions, deductive and inductive reasoning, and falsifiability. Approaches to research: the case study, naturalistic observation, observer bias and inter-rater reliability, surveys, samples and populations, archival research, and longitudinal versus cross-sectional designs. Analyzing findings: the correlation coefficient, positive and negative correlation, why correlation is not causation, confounding and illusory correlations, independent and dependent variables, experimental and control groups, single- and double-blind studies, the placebo effect, random sampling and random assignment, statistical significance, reliability and validity, and peer review and replication. And research ethics: the IRB, informed consent, deception and debriefing, the IACUC and animal welfare, and the Tuskegee syphilis study that led to the National Research Act.
- Sound (Physics)Recall cards on sound as a longitudinal disturbance of matter that travels outward through a medium. Compressions and rarefactions, the sinusoidal pressure and displacement variations and their quarter-cycle phase difference, and the wave-speed relation v = omega/k = lambda*f. The speed of sound: about 331 m/s in dry air at 0 C, 343 m/s at 20 C, its dependence on absolute temperature v = 331*sqrt(T/273 K), and the forms v = sqrt(Y/rho) in a solid rod and v = sqrt(gamma R T/M) in an ideal gas. Sound intensity I = P/A, the inverse-square falloff, the pressure-amplitude relation, the threshold of hearing 10^-12 W/m^2, and the decibel scale beta = 10 log10(I/I0). Standing sound waves and normal modes: nodes and antinodes, tubes open at both ends (all harmonics, lambda_1 = 2L) versus closed at one end (odd harmonics only, lambda_1 = 4L), fundamentals, overtones, and harmonics. Sources of musical sound and timbre, the end correction, beats and the beat frequency |f1 - f2|, the Doppler effect for moving source and moving observer, and shock waves, the Mach number, the sonic boom, and the shock-cone half-angle sin(theta) = 1/M.
- Nuclear Physics (Physics)Recall cards on nuclear physics. Properties of nuclei: protons, neutrons, nucleons, atomic and mass numbers, isotopes, the atomic mass unit, nuclear radius and density, and the strong nuclear force. Nuclear binding energy, the mass defect, binding energy per nucleon, and the stability of iron-56. Radioactive decay, the decay law and decay constant, half-life, activity, the becquerel and curie, and carbon-14 dating. Alpha, beta, and gamma decay with their changes in Z and A and their penetrating power. Nuclear fission, chain reactions, critical mass, and the liquid drop model. Nuclear fusion, the proton-proton chain in the Sun, and the deuterium-tritium reaction. Medical applications and biological effects: technetium-99m, PET imaging, the gray, the rad, relative biological effectiveness, and the sievert.
- The Endocrine SystemRecall cards on the animal endocrine system: hormones as chemical signals and their three chemical classes (lipid-derived steroids, amino acid-derived hormones, and peptide hormones) with their solubility, transport, and half-lives; how hormones work (receptor up- and down-regulation, intracellular versus cell-surface receptors, and the first- and second-messenger G-protein, adenylyl cyclase, cAMP, and protein-kinase cascade with amplification); regulation of body processes (ADH and aquaporins, aldosterone and the renin-angiotensin system, the reproductive axis, insulin and glucagon and diabetes, the thyroid hormones and calcium regulation, growth hormone, and the short- and long-term stress responses); the humoral, hormonal, and neural stimuli and negative feedback that control hormone release; and the endocrine glands (hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, pineal) plus secondary endocrine organs.
- Fluid Mechanics (Physics)Recall cards on the mechanics of fluids at rest and in motion. Density rho = m/V, specific gravity, and the states of matter. Pressure p = F/A as a scalar that acts equally in all directions and increases with depth as p = p0 + rho g h. Measuring pressure: gauge versus absolute pressure, the pascal and other units, and the barometer and manometer. Pascal's principle and how hydraulic systems multiply force without creating extra work. Archimedes' principle and buoyancy: the buoyant force equals the weight of displaced fluid, and floating, sinking, and apparent weight follow from density. Fluid dynamics: flow rate, the equation of continuity, laminar versus turbulent flow, and ideal fluids. Bernoulli's equation as energy conservation along a streamline, Bernoulli's principle relating speed and pressure, and entrainment. Finally viscosity, the Reynolds number, Poiseuille's law and its strong dependence on tube radius, and the onset of turbulence.
- Geometric Optics and Image Formation (Physics)Recall cards on geometric optics and image formation. Plane mirrors: same-size, upright, virtual images located as far behind the mirror as the object is in front, and the real-versus-virtual image distinction. Spherical mirrors: concave and convex geometry, center of curvature, vertex, optical axis, focal point, f = R/2, the mirror equation 1/d_o + 1/d_i = 1/f, magnification m = -d_i/d_o, and sign conventions. Images formed by refraction: apparent depth h_i = (n2/n1) h_o and the single-spherical-surface equation. Thin lenses: converging and diverging behavior, the thin-lens equation, the lensmaker's equation, ray tracing, and image types. The eye: cornea and lens, accommodation, near and far points, optical power in diopters, and correction of myopia and hyperopia. The camera, the simple magnifier and angular magnification, and compound microscopes and telescopes.
- Lifespan Development (Psychology)Recall cards on how humans develop from conception through death. What lifespan development studies: the physical, cognitive, and psychosocial domains, the normative approach and developmental milestones, continuous versus discontinuous development, stage theories, and the nature versus nurture debate. Major theories: Freud's five psychosexual stages and fixation, Erikson's eight psychosocial stages, Piaget's cognitive stages with assimilation, accommodation, object permanence, egocentrism, and conservation, and Kohlberg's preconventional, conventional, and postconventional moral reasoning. Stages of development: the germinal, embryonic, and fetal prenatal stages, the placenta, teratogens and FASD, newborn reflexes (rooting, sucking, grasping, Moro), infant growth and brain blooming and pruning, temperament, Harlow and Bowlby on attachment, Ainsworth's Strange Situation and the attachment styles, Baumrind's parenting styles, puberty and primary and secondary sexual characteristics, menarche and spermarche, adolescence and emerging adulthood, menopause, and crystallized versus fluid intelligence. Death and dying: Kubler-Ross's five stages, hospice care, living wills, DNR orders, and health care proxies.
- Orbits and Gravity (Astronomy)Recall cards on how the motions of the planets were measured and finally explained. Tycho Brahe's 20 years of observations and Kepler's three laws of planetary motion: elliptical orbits, foci and eccentricity, the law of equal areas, and P squared = a cubed. Newton's synthesis: his three laws of motion, momentum, mass, velocity, acceleration, density, and angular momentum. The universal law of gravitation, the inverse-square force, the gravitational constant, and Newton's mass-bearing form of Kepler's third law. Orbits in the solar system: perihelion and aphelion, the eight planets, the asteroid belt, and comets. Satellites and spacecraft: circular and escape speeds, orbital decay, and gravity assists (Voyager 2). Finally, gravity with many bodies: perturbations and the prediction and discovery of Neptune that confirmed Newton's laws.
- Temperature and Heat (Physics)Recall cards on temperature, heat, and heat transfer. Temperature as what a thermometer measures and as a measure of average translational kinetic energy, thermal equilibrium, and the zeroth law of thermodynamics. The Celsius, Fahrenheit, and Kelvin scales, their fixed points, the conversion formulas, and absolute zero (0 K = -273.15 C). Thermal expansion: linear (delta L = alpha L delta T), area (delta A = 2 alpha A delta T), and volume (delta V = beta V delta T with beta = 3 alpha), thermal stress, and water's density maximum near 4 C. Heat, the calorie and the mechanical equivalent of heat (1 kcal = 4186 J), specific heat and Q = mc delta T, and calorimetry (Q_cold + Q_hot = 0). Phase changes: melting, vaporization, and sublimation, the pressure dependence of melting and boiling points, latent heats of fusion and vaporization (water 334 kJ/kg and 2256 kJ/kg), phase diagrams, the triple point, and the critical point. The three mechanisms of heat transfer: conduction (P = kA(T_h - T_c)/d and the R-factor), convection (forced and natural), and radiation via the Stefan-Boltzmann law P = sigma A e T^4.
- Prokaryotes: Bacteria and ArchaeaRecall cards on prokaryotes: their diversity (prokaryotes as Earth's first cells, microbial mats and stromatolites, the oxygenation of the atmosphere, extremophiles, culturing and biofilms); the structure of Bacteria and Archaea (cell shapes, walls and membranes, the nucleoid and plasmids, reproduction and gene transfer, and the molecular differences between the two domains); prokaryotic metabolism (macronutrients, nutritional categories, and the nitrogen and carbon cycles); and bacterial diseases in humans (epidemics and pandemics, plague, typhoid, Lyme disease, foodborne illness, biofilms, and antibiotic resistance).
- States of Consciousness (Psychology)Recall cards on consciousness and sleep. Consciousness and wakefulness; biological and circadian rhythms, the suprachiasmatic nucleus, melatonin and the pineal gland, chronotype, jet lag, shift work, and sleep debt. Why we sleep: circadian and homeostatic control, the thalamus, hypothalamus, and pons, adaptive and evolutionary theories, and memory consolidation. Stages of sleep: the EEG, brain wave frequency and amplitude, beta, alpha, theta, and delta waves, NREM stages N1 to N3, sleep spindles and K-complexes, REM and paradoxical sleep, REM rebound, and dreaming (Freud's manifest and latent content, Jung's collective unconscious, activation-synthesis, and lucid dreams). Sleep problems and disorders: insomnia, parasomnias, sleepwalking, REM sleep behavior disorder, restless leg syndrome, night terrors, sleep apnea, SIDS, narcolepsy, and cataplexy. Substance use and abuse: dependence, tolerance, and withdrawal, and the depressant, stimulant, opioid, and hallucinogen drug classes. And other states of consciousness: hypnosis and meditation.
- Biochemistry of the Genome (Microbiology)Recall cards on the biochemistry of the genome. The classic experiments that revealed DNA as the genetic material: Miescher's nuclein, Kossel's bases, the Mendel and chromosomal-theory work of Boveri, Sutton, and Morgan, Beadle and Tatum's one gene-one enzyme hypothesis, McClintock's transposons, Griffith's transformation, the Avery-MacLeod-McCarty identification of DNA, and the Hershey-Chase experiment. The structure and function of DNA: nucleotides and nucleosides, deoxyribose, purines and pyrimidines, phosphodiester bonds, complementary base pairing and hydrogen bonds, Chargaff's rules, the antiparallel right-handed double helix, major and minor grooves, and denaturation and reannealing. The structure and function of RNA: ribose and uracil, single strands, messenger RNA, ribosomal RNA and ribozymes, transfer RNA and anticodons, and transcription and translation. And the structure and function of cellular genomes: genome, gene, genotype and phenotype, constitutive and housekeeping genes, prokaryotic versus eukaryotic chromosomes, ploidy, supercoiling and topoisomerases, histones and chromatin, plasmids, noncoding DNA and epigenetics, and representative genome sizes.
- Microbial Biochemistry (Microbiology)Recall cards on microbial biochemistry. Organic molecules: what makes a molecule organic, the macronutrient and trace elements of cells, carbon's four-bond valence and chain shapes, structural isomers and chiral enantiomers, the hydroxyl, carboxyl, amino, phosphate, and sulfhydryl functional groups, monomers and polymers, and dehydration synthesis. Carbohydrates: the (CH2O)n formula, aldoses and ketoses, trioses through hexoses, glycosidic bonds and the disaccharides maltose, lactose, and sucrose, and the polysaccharides cellulose, starch, glycogen, and chitin, plus NAG and NAM in peptidoglycan. Lipids: fatty acids saturated and unsaturated, triglycerides, amphipathic phospholipids and the bilayer, isoprenoids, and the sterols cholesterol, ergosterol, and hopanoids. Proteins: amino-acid structure and the R group, peptide bonds and residues, oligo- and polypeptides, the four levels of protein structure, disulfide bridges, denaturation, and glyco- and lipoproteins. And using biochemistry to identify microorganisms: PHB in Pseudomonas, the Biolog system, MALDI-TOF mass spectrometry, FAME analysis, proteomics, and Lancefield serological grouping.
- Seedless PlantsRecall cards on seedless plants: the origin of land plants within the Archaeplastida and the four adaptations to land (alternation of generations, apical meristems, waxy cuticle, and lignin); alternation of generations, sporangia, homospory and heterospory, sporopollenin, gametangia, and vascular tissue; the green algae (chlorophytes and charophytes) as precursors of land plants; the bryophytes (liverworts, hornworts, and mosses) with their dominant gametophytes and flagellated sperm; and the seedless vascular plants (lycophytes and the monilophytes: whisk ferns, horsetails, and ferns) with their dominant sporophytes, xylem and phloem, sporophylls and strobili, fronds and sori, and their ecological and human uses.
- Therapy and Treatment (Psychology)Recall cards on the therapy and treatment of psychological disorders. History of treatment: supernatural attributions, exorcism, trephining, the witch trials, asylums, Pinel and Dorothea Dix, the arrival of antipsychotics, deinstitutionalization and its failures, voluntary versus involuntary treatment, and mental health parity. Types of treatment: psychotherapy versus biomedical therapy; psychoanalysis (free association, resistance, transference, dream analysis); play therapy; behavior therapy (counterconditioning, aversive conditioning, exposure therapy, systematic desensitization, token economies); cognitive and cognitive-behavioral therapy (Beck, Ellis, cognitive distortions); humanistic and client-centered therapy (Rogers, unconditional positive regard, active listening); and biomedical options (psychotropic medications, ECT, TMS). Treatment modalities: intake, individual, group, couples, and family therapy (systems, structural, and strategic approaches). Substance-related and addictive disorders: addiction as a chronic disease, relapse, comorbidity, detoxification, and treatment duration. The sociocultural model: cultural competence, multicultural counseling, and barriers to therapy utilization such as stigma and language.
- Units and Measurement (Physics)Recall cards on units and measurement: the scope and scale of physics (physics as a science, orders of magnitude, models, theories, and laws, and the length, mass, and time scales of the universe); units and standards (physical quantities, base versus derived quantities, the seven SI base quantities and units, the modern second and meter standards, and metric prefixes); unit conversion with conversion factors; dimensional analysis (the base-dimension symbols L, M, T, I, theta, N, and J, dimensionless quantities, dimensional consistency, and transcendental arguments); estimates and Fermi calculations; significant figures (accuracy versus precision, uncertainty versus discrepancy, percent uncertainty, counting significant figures, and the rules for arithmetic operations and exact numbers); and the three-stage strategy for solving physics problems.
- Stoichiometry of Chemical Reactions (Chemistry)Recall cards on the stoichiometry of chemical reactions: writing and balancing chemical equations (reactants, products, coefficients, subscripts, conservation of matter, state symbols, and molecular, complete-ionic, and net-ionic equations); classifying chemical reactions (precipitation and solubility rules; Arrhenius acids and bases, strong versus weak, and neutralization; oxidation-reduction, oxidation numbers, oxidizing and reducing agents, combustion, and single displacement); reaction stoichiometry (the mole ratio and mass-to-mass calculations); reaction yields (limiting and excess reactants, and theoretical, actual, and percent yield); and quantitative chemical analysis (titration, gravimetric analysis, and combustion analysis).
- The Big Bang (Astronomy)Recall cards on the origin and evolution of the whole universe. The age of the cosmos: the Hubble time, the 13.8-billion-year-old universe, the deceleration that gave way to dark-energy acceleration, and the 1998 Type Ia supernova result honored with the 2011 Nobel Prize. A model of the universe: the homogeneous and isotropic large-scale cosmos, the scale factor, cosmological redshift, critical density, and open, closed, and flat geometries. The beginning: the Big Bang, Lemaitre's primeval atom, Gamow's hot early universe, the temperature-time ladder, and the nucleosynthesis of hydrogen, helium, and lithium in the first four minutes. The cosmic microwave background: Penzias and Wilson, the 2.73-kelvin blackbody, recombination at 380,000 years, and the COBE, WMAP, and Planck missions. What the universe is made of: about 4% ordinary matter, 27% dark matter, and 68% dark energy. And the frontier ideas: inflation and the flatness and horizon problems, the four fundamental forces, grand unified theories, the anthropic principle, cosmic fine-tuning, and the multiverse.
- Cosmic Samples and the Origin of the Solar System (Astronomy)Recall cards on the cosmic samples that reach Earth and what they reveal about how the solar system formed. Meteors, the shooting stars produced when tiny particles burn up in the atmosphere, and the meteor showers Earth meets when it crosses a comet's debris stream, from the Perseids to the Leonids. Meteorites, the fragments that survive to the ground: the iron, stony, and stony-iron classes, primitive versus differentiated bodies, and the amino acids in the Murchison meteorite that date the solar system to about 4.56 billion years. The solar nebula model of formation: a collapsing spinning disk, the condensation sequence that split the rocky inner planets from the icy giants, planetesimal accretion, and differentiation. What other planetary systems teach us, found by the Doppler and transit methods and by Kepler: super-Earths, hot Jupiters, and planetary migration. And the long-term evolution of worlds, where size governs how long a planet stays geologically alive, from the dead Moon to plate-tectonic Earth and Olympus Mons on Mars.
- How We See the Invisible World (Microbiology)Recall cards on the science of microscopy. The properties of light: wavelength, amplitude, frequency, reflection, absorption, transmission, diffraction, interference, refraction and refractive index, convex and concave lenses, the visible spectrum, dispersion, fluorescence and phosphorescence, and magnification, resolution, and numerical aperture. Peering into the invisible world: Fracastoro's seeds of contagion, van Leeuwenhoek the Father of Microbiology, Hooke and Micrographia, cork cells, simple versus compound microscopes, and Galileo and the Janssens. Instruments of microscopy: total magnification, brightfield, oil immersion, darkfield, phase-contrast, DIC, fluorescence, confocal, two-photon, electron (TEM and SEM), and scanning probe (STM and AFM) microscopes. Staining specimens: fixation, chromophores and basic versus acidic dyes, simple versus differential staining, the Gram stain, acid-fast, endospore, capsule, and flagella staining.
- Laboratory Analysis of the Immune Response (Microbiology)Recall cards on the laboratory analysis of the immune response. Producing antibodies: epitopes, affinity and avidity, cross-reactivity, polyclonal antisera and adjuvants, monoclonal antibodies and hybridomas, humanized antibodies and Herceptin, plantibodies and ZMapp, and test sensitivity and specificity. Detecting antigen-antibody complexes: precipitin reactions with the zones of equivalence and excess, the precipitin ring test, titers, Ouchterlony and radial immunodiffusion, flocculation and the VDRL test, viral neutralization assays, immunoelectrophoresis, the western blot, and complement fixation. Agglutination assays: direct and indirect (latex) agglutination, blood typing and cross-matching, the direct and indirect Coombs' tests, viral hemagglutination and hemagglutination inhibition, seroconversion, and the Widal and rheumatoid factor tests. EIAs and ELISAs: reporter enzymes and chromogens, direct, sandwich, and indirect ELISAs, lateral flow assays, and immunohistochemistry. And fluorescent antibody techniques: direct and indirect fluorescent antibody tests, antinuclear antibody testing, flow cytometry with CD4 counts, and fluorescence-activated cell sorting.
- The Kinetic Theory of Gases (Physics)Recall cards on the kinetic theory of gases. The ideal gas law in molecular form (pV = N k_B T) and molar form (pV = nRT), the Boltzmann constant, Avogadro's number, the universal gas constant R = N_A k_B, moles and molar mass, and the empirical Boyle, Charles, and Amonton laws. Standard temperature and pressure, the 22.4 L molar volume, and the van der Waals equation for real gases. The molecular model: kinetic-theory assumptions, pressure from wall collisions (pV = (1/3) N m (v^2)avg), average translational kinetic energy K_avg = (3/2) k_B T, the rms speed v_rms = sqrt(3 k_B T / m) = sqrt(3 R T / M), monatomic internal energy (3/2) nRT, Dalton's law of partial pressures, and the mean free path and mean free time. Heat capacity and equipartition: C_V at constant volume, degrees of freedom, the equipartition theorem, C_V = (d/2) R for monatomic (3/2 R), diatomic (5/2 R), and polyatomic (3R) gases, the Dulong-Petit law for solids (3R), and temperature-activated degrees of freedom. The Maxwell-Boltzmann distribution of molecular speeds, the most probable, average, and rms speeds and their ordering (v_p < v_avg < v_rms), and how the distribution shifts with temperature and molecular mass.
- The Death of Stars (Astronomy)Recall cards on how stars end their lives. Low-mass deaths: the Chandrasekhar limit, electron-degenerate white dwarfs, their carbon-oxygen-neon composition and extreme density, and their fade to black dwarfs. The explosive finish of massive stars: the onion-shell interior fusing up to iron, core collapse into neutrons and neutrinos, and the type II supernova that seeds space with the heaviest elements. Observed supernovae from SN 1006 to SN 1987A. Neutron stars and pulsars: their size, density, and surface gravity, Jocelyn Bell's 1967 discovery, the lighthouse model, and magnetars. Binary evolution: novae, type Ia supernovae, and millisecond pulsars. And the gamma-ray bursts, short from merging neutron stars and long from collapsing massive stars.
- Between the Stars: Gas and Dust in Space (Astronomy)Recall cards on the interstellar medium, the gas and dust between the stars. The mix: about 99% gas and 1% dust, mostly hydrogen and helium, totaling roughly 15% of the Galaxy's stellar mass. Interstellar gas: hot ionized H II regions and their red H-alpha glow, cool neutral hydrogen and the 21-centimeter line, ultra-hot supernova gas, and cold giant molecular clouds rich in molecules. Cosmic dust: tiny grains with rocky cores and icy mantles that cause extinction, reddening, and reflection and dark nebulae. Cosmic rays: high-speed nuclei and electrons, mostly protons, arriving near light speed. The life cycle of cosmic material as stars return enriched gas and dust to space. And the Sun's own neighborhood, the hot Local Bubble and the Local Fluff cloud around us.
- Seed PlantsRecall cards on seed plants: the evolutionary advantages of pollen and seeds, the reduction of the gametophyte, and the fossil timeline from progymnosperms through gymnosperm dominance to the rise of the angiosperms; the gymnosperms (conifers, cycads, ginkgo, and gnetophytes) with their naked seeds, cones, tracheid wood, and wind-and-insect pollination; the angiosperms (flower structure, the carpel and stamen, double fertilization and endosperm, fruit, and the split among basal angiosperms, monocots, and eudicots); and the roles of seed plants as food, fiber, fuel, and medicine, their coevolution with pollinators and herbivores, and their part in stabilizing ecosystems.
- The Birth of Stars and the Discovery of Planets outside the Solar System (Astronomy)Recall cards on how stars are born and how we find planets around other stars. Star formation in giant molecular clouds: their cold, filamentary interiors, the dense clumps and cores that collapse, and the vivid example of the Orion molecular cloud and its nebula. The stages of a forming star: protostars, whirling protostellar disks, T Tauri stars, stellar winds, and the jets that light up Herbig-Haro objects. Reading stellar evolution off the H-R diagram: evolutionary tracks, the 12-million-K threshold for reaching the main sequence, and the mass limits of true stars. Evidence that planets form in circumstellar disks, growing by accretion from dust grains to planetesimals to giant planets. And the exoplanet revolution: 51 Pegasi b, the radial-velocity and transit methods, direct imaging, Kepler's harvest, super-Earths and mini-Neptunes, and planetary migration.
- Thinking and Intelligence (Psychology)Recall cards on cognition, language, problem solving, and intelligence. Cognition: concepts and prototypes, natural versus artificial concepts, and schemas, role schemas, and event schemas. Language: the lexicon, grammar, phonemes, morphemes, semantics, and syntax, plus babbling, overgeneralization, linguistic determinism, the Sapir-Whorf hypothesis, the critical period, and the Boroditsky and Dani color studies. Problem solving: trial and error, algorithms, heuristics, working backwards, mental set, and functional fixedness, plus the anchoring, confirmation, hindsight, and representative biases and the availability heuristic. Intelligence: Spearman's g, Cattell's fluid and crystallized intelligence, Sternberg's triarchic theory, Gardner's multiple intelligences, emotional intelligence, creativity, and divergent versus convergent thinking. Measurement: Galton, Binet, the Stanford-Binet, and the Wechsler WAIS and WISC scales, standardization, norming, reliability, validity, the normal distribution, IQ ranges, the Flynn effect, and Buck v. Bell and Atkins v. Virginia. Sources of intelligence: range of reaction, the Minnesota twin study, poverty and the prefrontal cortex, and learning disabilities including dysgraphia, dyslexia, and dyscalculia.
- Biotechnology and GenomicsRecall cards on biotechnology and genomics: the basic techniques (nucleic-acid isolation, gel electrophoresis, PCR and RT-PCR, Southern and Northern blotting, probes); molecular cloning (plasmid vectors, restriction endonucleases and sticky ends, DNA ligase, recombinant and chimeric DNA, the multiple cloning site); applications (recombinant insulin and growth hormone, reproductive and therapeutic cloning, somatic cell nuclear transfer and Dolly, genetic engineering, GMOs and transgenic organisms, gene therapy, Agrobacterium and the Ti plasmid, Bt crops, the Flavr Savr tomato, reverse genetics and gene targeting); mapping genomes (genetic versus physical maps, linkage analysis, RFLP, SNP and VNTR markers, cytogenetic, radiation-hybrid and sequence mapping, STSs and ESTs); whole-genome sequencing (Sanger chain termination and ddNTPs, shotgun and pairwise-end sequencing, next-generation sequencing, annotation and microarrays); and applied genomics and proteomics (pharmacogenomics, metagenomics, mitochondrial DNA, the proteome versus the genome, biomarkers and protein signatures, metabolomics and systems biology).
- Black Holes and Curved Spacetime (Astronomy)Recall cards on Einstein's general relativity and its most extreme prediction. The theory itself: the equivalence principle, spacetime curved by matter, and gravity as that curvature. The classic tests: Mercury's perihelion precession, the 1919 eclipse deflection of starlight, gravitational redshift and time dilation, and the relativistic corrections that keep GPS accurate. Black holes: the event horizon, the Schwarzschild radius, the singularity, spaghettification, and the core mass needed to form one. The evidence: X-ray binaries, accretion disks, Cygnus X-1, and the supermassive black holes at galactic centers. And gravitational-wave astronomy: the binary pulsar PSR 1913+16, LIGO, and the 2015 black-hole and 2017 neutron-star mergers.
- EcosystemsRecall cards on ecosystems: the ecology of ecosystems (freshwater, marine, and terrestrial categories; equilibrium, resistance, and resilience; food chains, trophic levels, and food webs; grazing and detrital food webs; and conceptual, analytical, and simulation models); energy flow through ecosystems (photoautotrophs and chemoautotrophs; gross and net primary productivity; trophic level transfer efficiency and net production efficiency; ecological pyramids of numbers, biomass, and energy; and biomagnification of DDT, PCBs, and heavy metals); and biogeochemical cycles (the water, carbon, nitrogen, phosphorus, and sulfur cycles, including nitrogen fixation, ammonification, nitrification, and denitrification, eutrophication and dead zones, and acid rain).
- Essential Ideas (Chemistry)Recall cards on the essential ideas of chemistry: chemistry in context (the central science; hypothesis, law, and theory; the macroscopic, microscopic, and symbolic domains); phases and classification of matter (the states of matter and plasma; mass versus weight; conservation of matter; pure substances, elements, compounds, and mixtures; atoms and molecules); physical and chemical properties and changes (extensive versus intensive properties; the NFPA hazard diamond); measurements (SI base units and metric prefixes; volume and density); measurement uncertainty (significant figures, rounding, accuracy versus precision); and the mathematical treatment of measurements (dimensional analysis, conversion factors, and temperature scales).
- Plant ReproductionRecall cards on plant (angiosperm) reproduction: alternation of generations and flower anatomy (the four whorls, complete vs incomplete, monoecious vs dioecious); development of the male and female gametophytes; pollination (self vs cross, self-incompatibility, and animal, wind, and water pollinators); double fertilization, embryo and seed structure, germination, and fruit types and seed dispersal; and asexual reproduction, vegetative propagation, and plant life spans.
- ProtistsRecall cards on protists: eukaryotic origins (the defining nucleus, the single eukaryotic ancestor, endosymbiotic theory, and the bacterial origins of mitochondria and plastids by primary and secondary endosymbiosis); the general characteristics of protists (habitats, nutrition, motility, cell coverings, and reproduction); the major groups across the six eukaryotic supergroups (Excavata, Chromalveolata, Archaeplastida, Rhizaria, Amoebozoa, and Opisthokonta, with their representative diplomonads, parabasalids, euglenozoans, dinoflagellates, apicomplexans, ciliates, diatoms, algae, foraminiferans, radiolarians, amoebas, slime molds, and choanoflagellates); and the ecology of protists (primary production, symbioses with coral, and human diseases such as malaria, sleeping sickness, Chagas disease, and potato blight).
- Thermochemistry (Chemistry)Recall cards on thermochemistry: energy basics (energy, work, kinetic and potential energy, conservation of energy, thermal energy, temperature, heat, exothermic and endothermic processes, the calorie and joule, heat capacity, specific and molar heat capacity, and q = m c deltaT); calorimetry (calorimeters, system and surroundings, coffee-cup and bomb calorimeters, hand warmers and cold packs, and food energy); and enthalpy (internal energy, the first law of thermodynamics, pressure-volume work, state functions, enthalpy and enthalpy change, thermochemical equations, standard states, standard enthalpies of combustion and formation, and Hess's law).
- Vectors (Physics)Recall cards on vectors: scalars versus vectors (magnitude and direction, notation, displacement, equal, parallel, antiparallel, orthogonal, and negative vectors, scalar multiplication, resultants, the commutative, associative, and distributive laws, the parallelogram and tail-to-head rules, unit vectors, and vector subtraction); coordinate systems and components (vector and scalar components, the unit vectors i-hat, j-hat, and k-hat, component form, magnitude and direction angle from components, quadrant rules, polar coordinates, and right-handed axes); the algebra of vectors (the analytical component method, component-wise addition, subtraction, and scalar multiplication, equality, the null vector, and unit vectors from magnitude); and the products of vectors (the scalar or dot product and the vector or cross product, their properties, unit-vector identities, component forms, and the applications to work and torque).
- Egyptian MythologyDiscover the gods, pharaohs, and mysteries of ancient Egypt
- Social Psychology (Psychology)Recall cards on social psychology: how people affect one another and how situations and groups shape individual behavior. Situationism versus dispositionism and the attribution biases (the fundamental attribution error, the actor-observer bias, the self-serving bias, and the just-world hypothesis). Self-presentation: social roles, social norms, scripts, and Zimbardo's Stanford prison experiment. Attitudes and persuasion: the affective, behavioral, and cognitive components, Festinger's cognitive dissonance, the Yale attitude change approach, the elaboration likelihood model with its central and peripheral routes, and the foot-in-the-door technique. Conformity, compliance, and obedience: Asch's line studies and the Asch effect, normative versus informational social influence, Milgram's obedience experiment, groupthink, group polarization, social loafing, and deindividuation. Prejudice and discrimination: stereotypes, racism, sexism, ageism, homophobia, in-groups and out-groups, in-group bias, scapegoating, self-fulfilling prophecy, and confirmation bias. Aggression: hostile versus instrumental aggression, the frustration-aggression theory, bullying and cyberbullying, the bystander effect, and diffusion of responsibility. Prosocial behavior: altruism, empathy, proximity, homophily, self-disclosure, reciprocity, the matching hypothesis, Sternberg's triangular theory of love, and social exchange theory.
- Condensed Matter Physics (Physics)Recall cards on condensed matter physics. Molecular bonding by ionic, covalent, and van der Waals forces, the energetics of NaCl and H2 formation, and molecular rotational and vibrational spectra. Bonding in crystalline solids, the Madelung constant, and dissociation energy. The free electron model of metals, the Fermi energy, the Fermi factor, and the density of states. Band theory, valence and conduction bands, and the energy gaps that distinguish conductors, insulators, and semiconductors. Doping, n-type and p-type material, holes, the p-n junction, diodes, and transistors. Superconductivity, the Meissner effect, critical fields, Cooper pairs and BCS theory, and high-temperature superconductors.
- Conservation Biology and BiodiversityRecall cards on conservation biology and biodiversity: the biodiversity crisis (genetic, species, and ecosystem diversity; how many species exist and how many are named; the equatorial gradient, endemism, and biodiversity hotspots; the five mass extinctions and the present sixth; background versus current extinction rates; and the species-area relationship); the importance of biodiversity to human life (medicines from plants and animals; crop wild relatives and seed banks; soil organisms, pollinators and colony collapse, natural pest control, and fisheries); threats to biodiversity (habitat loss, overharvesting, invasive species, and climate change); and preserving biodiversity (DNA barcoding; CITES, the Endangered Species Act, and the Migratory Bird Treaty Act; nature preserve design and island biogeography; keystone species; and captive breeding).
- Current and Resistance (Physics)Recall cards on electric current, resistance, and superconductors. Electrical current: current as the rate of charge flow, I = dQ/dt, the ampere and its name, the need for a complete circuit, conventional current, electron carriers in metals, carriers in ionic solutions, and drift velocity. Model of conduction in metals: the free-electron sea, the zig-zag drift path, signal speed versus drift speed, I = nqAv_d, current as a scalar, current density J as a vector, J = nqv_d, E = rho J, and why good electrical conductors conduct heat. Resistivity and resistance: resistivity rho, its reciprocal conductivity, the ohm-meter, conductor versus insulator versus semiconductor, R = V/I, R = rho L/A, the ohm, the temperature dependence rho = rho_0[1 + alpha(T - T_0)], and the temperature coefficient alpha. Ohm's law: V = IR, Ohm's experiment, its empirical nature, ohmic versus nonohmic devices, and the diode. Electrical energy and power: P = IV, P = I^2 R, P = V^2/R, the watt, resistive heating, E = Pt, and the kilowatt-hour. Superconductors: zero resistance below a critical temperature, Onnes's discovery, mercury, the Meissner effect, Type I and Type II, YBCO, BCS theory and Cooper pairs, persistent currents, MRI magnets, SQUIDs, and the Josephson effect.
- FungiRecall cards on fungi: their defining characteristics (chitin cell walls, ergosterol membranes, hyphae, septa, mycelium, heterotrophic external digestion, and asexual and sexual reproduction through plasmogamy, karyogamy, and meiosis); the five phyla (Chytridiomycota, Zygomycota, Ascomycota, Basidiomycota, and Glomeromycota) plus the former imperfect fungi; the ecology of fungi (decomposition, mycorrhizae, lichens, endophytes, and symbioses with ants); fungal parasites and pathogens (ergot, mycoses, dermatophytes, and diseases of humans, bats, and frogs); and the importance of fungi in human life (food, fermentation, antibiotics, immunosuppressants, model organisms, and mycorrhizal support of plant life).
- Magnetic Forces and Fields (Physics)Recall cards on magnetic forces and fields. Magnets and Earth's field: the two poles, attraction and repulsion, the absence of magnetic monopoles, Earth as a bar magnet, compass behavior, field reversals, and the historical discoveries of Oersted, Ampere, Arago, and Faraday. The magnetic field: its definition through the force on a moving charge, F = qv x B, F = qvB sin(theta), the tesla and gauss, the right-hand rule, and field lines. Motion of a charged particle: circular and helical paths, why the magnetic force does no work, r = mv/(qB), the period T = 2 pi m/(qB), pitch, magnetic bottles, and the Van Allen belts. Force on a current-carrying conductor: RHR-2, F = IL x B, F = BIL sin(theta), and the zero net force on a closed loop. Force and torque on a current loop: the magnetic dipole moment mu = NIA, tau = mu x B, tau = IAB sin(theta), the potential energy U = -mu . B, electric motors, and the commutator. The Hall effect: Hall's experiment, the Hall voltage, the force balance, drift speed, velocity selectors, and identifying charge carriers. Applications: the mass spectrometer and the cyclotron.
- Disease and Epidemiology (Microbiology)Recall cards on the epidemiology of infectious disease. The language of epidemiologists: etiology, morbidity and mortality rates, prevalence versus incidence, sporadic, endemic, epidemic, and pandemic disease, and notifiable diseases tracked through the NNDSS and reported in the MMWR. Tracking infectious disease: the pioneers (Snow, Nightingale, Lister), common source versus propagated spread, and descriptive, analytical, retrospective, and prospective study designs. Modes of transmission: reservoirs and carriers, direct and indirect contact, droplet, airborne, vehicle, and vector spread, and healthcare-associated infections. And global public health: the role of the WHO, the eradication of smallpox, and emerging and reemerging infectious diseases.
- Astronomical Instruments (Astronomy)Recall cards on the telescopes and detectors astronomers use to study the universe. Telescopes: their light-gathering and focusing functions, aperture and collecting area, refractors versus reflectors, chromatic aberration, the Newtonian and Cassegrain focus, and the history from Lippershey and Galileo to Newton's first reflector and the great refractors. Telescopes today: the 8-to-10-meter giants (Keck, Gran Telescopio Canarias, VLT, Subaru, Gemini, Hale), segmented mirrors, high and dark sites, and active and adaptive optics. Detectors: photographic plates, CCDs, imaging versus spectroscopy, diffraction gratings, and cooled infrared detectors. Radio telescopes: Jansky and Reber, dishes and receivers, Green Bank, Arecibo, and FAST, and interferometry from the VLA and ALMA to the VLBA. Space observatories: Hubble, IRAS, Spitzer, JWST, SOFIA, Chandra, and Fermi. And the future giants: the ELT, TMT, GMT, Vera Rubin Observatory, and the Cherenkov Telescope Array.
- The First Law of Thermodynamics (Physics)Recall cards on the first law of thermodynamics. Thermodynamic systems: system, boundary, and surroundings; open, closed, and isolated systems; thermal equilibrium and the zeroth law; equations of state f(p, V, T) = 0 and pV - nRT = 0; extensive versus intensive variables; and pV diagrams. Work, heat, and internal energy: dW = p dV, W as the integral of p dV and the area under a pV curve, the sign of work in expansion and compression, the path dependence of work, and the work in isothermal (nRT ln(V2/V1)), isobaric (p(V2 - V1)), and isochoric (zero) processes; internal energy as the total molecular energy, E_int = (3/2) nRT for a monatomic ideal gas, and the quasi-static process. The first law itself: Delta E_int = Q - W, the sign conventions for Q and W, the differential form dE_int = dQ - dW, internal energy as a path-independent state function, and the isothermal, cyclic, and isolated-system cases. Thermodynamic processes: isothermal, adiabatic, isobaric, isochoric, cyclic, and non-quasi-static, with Q = W for a cycle. Heat capacities of an ideal gas: C_V and C_p, Q = n C_V Delta T and Q = n C_p Delta T, dE_int = n C_V dT, Mayer's relation C_p = C_V + R, the monatomic, diatomic, and polyatomic values, and C_V = (d/2) R. Adiabatic processes: Q = 0, Delta E_int = -W, pV^gamma = constant, TV^(gamma-1) = constant, the adiabatic index gamma = C_p/C_V > 1, the steeper adiabatic slope, free expansion at constant temperature, and engine knocking.
- The Nature of Light (Physics)Recall cards on the nature of light. The propagation of light: the speed of light in vacuum, its invariance for all observers, the index of refraction n = c/v, and the ray model. The law of reflection: angle of reflection equals angle of incidence, specular versus diffuse reflection, corner reflectors, and retroreflectors. Refraction and Snell's law: bending toward or away from the normal, and representative indices for air, water, and diamond. Total internal reflection: the critical angle theta_c = arcsin(n2/n1) and optical fibers. Dispersion: white light spread into a spectrum, wavelength-dependent index, prisms, and rainbows. Huygens's principle: wavelets, wave fronts, refraction, and diffraction. Polarization: Malus's law, polarizing filters, Brewster's angle, birefringence, optical activity, and liquid-crystal displays.
- Active Galaxies, Quasars, and Supermassive Black Holes (Astronomy)Recall cards on active galactic nuclei and the supermassive black holes that power them. Quasars: the meaning of quasi-stellar radio source, their 1950s discovery with surplus radar gear, Maarten Schmidt's 1963 reading of the huge redshift of 3C 273, the redshifts that reach 96% of the speed of light, the Hubble Space Telescope host galaxies, and the rapid variability that pins the emitting region to a few light-months. The engine: a central black hole fed by a friction-heated accretion disk, the roughly 10% mass-energy efficiency that dwarfs nuclear fusion, masses from under a million to tens of billions of Suns, M87 and the 2019 Event Horizon Telescope shadow, and jets launched near light speed. And cosmic evolution: the early peak of quasars and star formation, the 1/200 black-hole-to-galaxy mass ratio, tidal disruption events, seed black holes, mergers such as NGC 6240, and black-hole feedback on star birth.
- Earthlike Planets: Venus and Mars (Astronomy)Recall cards comparing Venus and Mars, Earth's two nearest planetary neighbors. The bulk and orbital data of each world: distance from the Sun, orbital period, diameter, mass, density, surface gravity, escape velocity, rotation, and surface conditions. The geology of Venus: its lowland lava plains, the absence of plate tectonics, the Aphrodite and Ishtar highlands, the Maxwell Mountains, its shield volcanoes and pancake domes, and how Magellan's radar and the Venera landers explored it. The crushing 90-bar, 96-percent carbon-dioxide atmosphere of Venus, its sulfuric-acid clouds, and the runaway greenhouse effect that makes it the hottest planet. The geology of Mars: Olympus Mons, the Valles Marineris canyons, the Tharsis bulge, its cratered southern highlands, and the Mariner and Viking missions. The evidence for water and life on Mars: its polar caps, runoff and outflow channels, recurring slope lineae, subsurface ice, and ancient lakebeds. And why three planets that began alike diverged into such different worlds.
- Electric Potential (Physics)Recall cards on electric potential energy, electric potential, and their applications. Electric potential energy: that the Coulomb force is conservative and path-independent, the symbol U and its joule unit, W = -delta U, the zero reference at infinity, the two-charge result U = k*q*Q/r, Coulomb's constant, and the zero closed-loop line integral. Electric potential and potential difference: V = U/q, the symbol V, test-charge independence, the volt as J/C, delta V = delta U/q, V_B - V_A, voltage, delta U = q*delta V, E = -delta V/delta s in a uniform field, 1 N/C = 1 V/m, and the electron-volt. Calculations of potential: V = k*q/r for a point charge, the 1/r versus 1/r^2 falloff, the scalar nature and algebraic superposition of potential, the electric dipole and its moment p = q*d, the integral form for a continuous distribution, and the far-field dipole potential. Field from potential: E = -dV/ds, the steepest-descent direction, E = -grad V, the partial-derivative components, and the scalar-first method. Equipotential surfaces and conductors: the definition and lines, perpendicularity to field lines, zero work along a surface, a conductor as an equipotential, grounding, and charge concentration at small radii of curvature. Applications: the Van de Graaff generator, xerography and the photoconductor, laser and ink-jet printers, and the electrostatic precipitator.
- Industrial-Organizational Psychology (Psychology)Recall cards on industrial and organizational (I-O) psychology: how work affects human behavior and how human behavior affects work. The three subfields (industrial, organizational, and human factors psychology) and the field's history: Munsterberg, Cattell's Psychological Corporation, the Army Alpha and Beta tests, the Hawthorne studies and the Hawthorne effect, Lewin's group dynamics, Taylor's scientific management, and Lillian Gilbreth. Industrial psychology: job analysis (task-oriented versus worker-oriented), KSAs, O*NET, structured versus unstructured interviews, training and mentoring, 360-degree feedback, and the employment law that governs selection (the EEOC, Title VII, the Equal Pay Act, the ADA, Griggs v. Duke Power Co., and bona fide occupational qualifications). Organizational psychology: job satisfaction, organizational citizenship behaviors, Theory X and Theory Y, transactional versus transformational leadership, organizational culture, virtual teams, strengths-based management, sexual harassment, and workplace violence. Human factors psychology (ergonomics): designing the human-machine interface for productivity, safety, and health, and checklists that reduce human error.
- Learning (Psychology)Recall cards on how organisms learn. What learning is: reflexes, instincts, associative learning, and the difference between classical, operant, and observational learning. Classical conditioning: Pavlov, the unconditioned and conditioned stimulus and response, the neutral stimulus, acquisition, higher-order conditioning, extinction, spontaneous recovery, stimulus discrimination and generalization, taste aversion, the Garcia and Koelling and Little Albert studies, behaviorism, and the Rescorla-Wagner model. Operant conditioning: Thorndike's law of effect, Skinner and the operant chamber, positive and negative reinforcement and punishment, primary and secondary reinforcers, shaping, continuous versus partial reinforcement, the fixed and variable interval and ratio schedules, and Tolman's cognitive maps and latent learning. Observational learning: models, mirror neurons, Bandura's social learning theory, live, verbal, and symbolic models, the attention-retention-reproduction-motivation steps, vicarious reinforcement and punishment, the Bobo doll experiment, and prosocial and antisocial modeling.
- Electromagnetic Waves (Physics)Recall cards on electromagnetic waves. Maxwell's equations: the displacement current that completes Ampere's law, the four laws (Gauss, Gauss for magnetism, Faraday, Ampere-Maxwell), how changing fields generate each other, the prediction of waves at the speed of light, and Hertz's confirmation. Plane waves: transverse fields perpendicular to each other and to propagation, E/B = c, the wave equation, c = 1/sqrt(epsilon0 mu0), and the E cross B direction. Energy: energy density, the Poynting vector, intensity, and the field amplitude relation E0 = c B0. Momentum and radiation pressure: p = U/c, absorber versus reflector pressure, comet tails, and light sails. The electromagnetic spectrum: c = f lambda, and radio, microwave, infrared, visible, ultraviolet, X-ray, and gamma-ray bands.
- Introduction to Animal DiversityRecall cards introducing the animal kingdom: the shared features of animals (heterotrophy, tissues, no cell walls, the diplontic life cycle, and the five clades from Parazoa to Bilateria); sexual, asexual, and parthenogenetic reproduction; embryonic development from cleavage through gastrulation, the germ layers, metamorphosis, and the Hox genes that pattern the body plan; the features used to classify animals (symmetry, germ layers, the coelom, and protostome versus deuterostome development); animal phylogeny (Eumetazoa, Radiata and Bilateria, Ecdysozoa and Lophotrochozoa, and choanoflagellate ancestry); and the evolutionary history of animals across the Ediacaran, the Cambrian explosion, and the later mass extinctions.
- Norse MythologyExplore the world of Vikings, Norse gods, and the Nine Realms
- Oscillations (Physics)Recall cards on oscillatory motion. Periodic motion, period and frequency, and amplitude. Simple harmonic motion (SHM) as the motion of a Hooke's-law restoring force: position x(t) = A cos(omega t + phi), its velocity and acceleration, angular frequency omega = sqrt(k/m), and the period T = 2 pi sqrt(m/k) that depends only on mass and spring constant. Energy in SHM: elastic potential and kinetic energy, the conserved total E = (1/2) k A^2 proportional to amplitude squared, and the speed at any position. SHM as the projection of uniform circular motion. Pendulums: the simple pendulum with T = 2 pi sqrt(L/g), the physical pendulum, and the torsional pendulum. Damped oscillations: the velocity-proportional damping force, exponential amplitude decay, and the underdamped, critically damped, and overdamped regimes. Forced oscillations: natural frequency, steady-state amplitude, and resonance when the driving frequency matches the natural frequency.
- Sensory SystemsRecall cards on animal sensory systems: how sensory reception, transduction, and perception work, receptor types and receptive fields, receptor potentials, the labeled-line principle, and Weber's Law; somatosensation (the skin layers and the four somatosensory receptor classes, the tactile mechanoreceptors, proprioceptors, baroreceptors, thermoreception, nociception, and two-point discrimination); taste and smell (the five tastes, papillae and taste buds, salt and sour versus sweet, bitter, and umami transduction, the olfactory epithelium and bulb, combinatorial odor coding, and pheromones); hearing and vestibular sensation (sound as pressure waves, the outer, middle, and inner ear, the cochlea and basilar membrane, place theory, and the utricle, saccule, and semicircular canals); and vision (light and the eye, refractive errors, rods and cones, rhodopsin phototransduction, trichromatic cones, retinal circuitry and lateral inhibition, and the pathway to the visual cortex).
- Analyzing Starlight (Astronomy)Recall cards on how astronomers read a star's light. Brightness: the difference between luminosity (total energy emitted per second) and apparent brightness (energy reaching us), the inverse-square dimming with distance, and Hipparchus's magnitude scale on which brighter means a smaller number and five magnitudes span a factor of 100. Color: a star's surface temperature sets its color, from over 40,000 K blue-white down to about 2,000 K red, quantified by the UBV color index. Spectra: the temperature-ordered OBAFGKM (plus L, T, Y) classes, their spectral-line signatures, brown dwarfs, and Annie Jump Cannon. And what spectra reveal: composition (about three-quarters hydrogen), radial velocity from the Doppler shift, proper motion across the sky, and rotation and pressure read from the width of the lines.
- Applications of Newton's Laws (Physics)Recall cards on applying Newton's laws: the systematic problem-solving strategy of sketching the situation, drawing a free-body diagram of the external forces, applying Newton's second law per coordinate axis, and checking the result; static and dynamic equilibrium, tension in a massless string over a frictionless pulley, apparent weight and elevator problems, and connected objects. Friction as a contact force opposing relative motion, static versus kinetic friction, the laws f_s <= mu_s N and f_k = mu_k N, the dimensionless coefficients of friction, area independence, and the microscopic origins of friction. Centripetal acceleration and force in uniform circular motion, F_c = m v^2/r = m r omega^2, ideally banked curves with theta = arctan(v^2/rg), inertial versus noninertial reference frames, and the fictitious centrifugal and Coriolis forces. And drag force through a fluid, F_D = (1/2) C rho A v^2, the drag coefficient, terminal velocity v_T = sqrt(2mg/(rho C A)), and Stokes' law for small slow objects.
- Direct-Current Circuits (Physics)Recall cards on direct-current circuits. Electromotive force: emf as work per unit charge, the symbol epsilon, the volt, energy conversion, terminal voltage, internal resistance r, V_terminal = emf - I r, I = emf/(R + r), and ideal versus real batteries. Resistors in series and parallel: the same current in series, R_S as a sum, the source voltage as a sum of drops, the same voltage in parallel, 1/R_P as a sum of reciprocals, branch currents summing to the total, and combination circuits. Kirchhoff's rules: junctions, the junction rule from charge conservation, the loop rule from energy conservation, and the sign conventions for resistors and emf sources. Electrical measuring instruments: the ammeter in series, the voltmeter in parallel, the galvanometer, converting it to an ammeter or voltmeter, and analog, digital, and ohmmeter designs. RC circuits: charging and discharging of a capacitor, the time constant tau = RC, the 63.2% and 36.8% marks, and a full capacitor as an open circuit. Household wiring and safety: thermal and shock hazards, short circuits, P = I^2 R_w, fuses and breakers, the live, neutral, and ground wires, grounding, and the GFCI.
- The Sun: A Garden-Variety Star (Astronomy)Recall cards on the Sun, the ordinary star at the center of our solar system, and the activity that plays across its surface. Its structure and composition: a ball of mostly hydrogen and helium a million kilometers wide, from the 15-million-degree core out through the convective zone to the visible photosphere, the thin chromosphere, and the tenuous but million-degree corona that launches the solar wind. The solar cycle: sunspots and their umbra and penumbra, the roughly 11-year rhythm of sunspot maxima, differential rotation, the Zeeman effect that maps magnetic fields, and the 22-year magnetic cycle driven by the solar dynamo. Solar activity above the photosphere: plages, prominences, flares, coronal mass ejections, and the active regions where strong magnetic fields tie them together. And space weather, the way particles and radiation from the Sun disturb Earth's magnetosphere, from the Carrington Event of 1859 and the 1989 Quebec blackout to the Maunder Minimum.
- Earth as a Planet (Astronomy)Recall cards studying Earth as one of the terrestrial planets. Its bulk properties: diameter, mass, record-high density, and escape velocity. Its layered interior built by differentiation: the basaltic oceanic and granitic continental crust, the deep mantle, the iron core, and the magnetic field and magnetosphere the liquid core produces. Its restless crust: igneous, sedimentary, and metamorphic rock, roughly a dozen tectonic plates driven by mantle convection, seafloor spreading, subduction, faults, continental drift, and hot spots. Its atmosphere: the nitrogen-oxygen-argon mix, sea-level pressure, the troposphere, stratosphere, and ionosphere, the ozone layer, and weather versus climate. The coevolution of life and air: the oldest rocks, stromatolites, the rise of oxygen, and present-day carbon dioxide and the greenhouse effect. And the cosmic impacts that have shaped Earth, from Tunguska and Chelyabinsk to Meteor Crater and the Chicxulub impact that ended the age of the dinosaurs.
- Fundamental Equilibrium Concepts (Chemistry)Recall cards on the fundamentals of chemical equilibrium: reversible reactions and dynamic equilibrium (equal forward and reverse rates, constant concentrations, the double arrow); the reaction quotient Q and the equilibrium constant K (the concentration form Qc and the pressure form Qp, the law of mass action, what large and small K values mean, using Q versus K to predict reaction direction, the relation Kp = Kc(RT)^delta-n, and homogeneous versus heterogeneous equilibria with pure solids and liquids omitted); manipulating equilibrium constants for reversed, multiplied, and combined reactions; Le Chatelier's principle (how concentration, pressure-volume, and temperature changes shift an equilibrium, why a catalyst does not, and the Haber process and carbonated-drink examples); and equilibrium calculations with ICE tables, the quadratic formula, and the small-K approximation.
- The Evolution and Distribution of Galaxies (Astronomy)Recall cards on how galaxies formed, grew, and arranged themselves across the cosmos. Looking back in time: the 13.8-billion-year-old universe, the first stars within a billion years, the more than 2 trillion galaxies, and the tiny, blue, low-mass early galaxies seen at high redshift. Galaxy mergers: collisions far more common in the past, starbursts that burn through their gas in a few million years, the Tadpole and its tidal tail, NGC 6240's twin black holes, and galactic cannibalism. Large-scale structure: the cosmological principle, the Local Group, the Virgo and Coma clusters, superclusters, voids, and the sponge-like cosmic web. Dark matter: galaxy rotation curves, cluster mass-to-light ratios, gravitational lensing, MACHOs, and cold versus hot dark matter. And the assembly of structure: top-down versus bottom-up formation, red-and-dead ellipticals, and a universe that is about 5% atoms, 27% dark matter, and 68% dark energy.
- Cratered Worlds: The Moon and Mercury (Astronomy)Recall cards studying the Moon and Mercury, the airless, heavily cratered worlds closest to home. The Moon's bulk properties: its diameter, mass, surface gravity, escape velocity, low density, and synchronous rotation, and why it holds no atmosphere. Its two terrains: the dark basaltic maria that flooded impact basins, the bright, ancient, heavily cratered highlands of anorthosite, the regolith, and its extreme day and night temperatures. The physics of impact cratering: impact speeds, the nuclear-scale blast, crater and ejecta sizes, bright rays, secondary craters, and how often craters of a given size form. The competing ideas for the Moon's origin, from the fission, sister, and capture hypotheses to the leading giant impact hypothesis. And Mercury: its eccentric orbit, huge iron core, 3-to-2 spin-orbit resonance, temperature extremes, shrinkage scarps, the Caloris basin, polar ice, and the Mariner 10 and MESSENGER missions that mapped it.
- Memory (Psychology)Recall cards on how memory works, its brain basis, its failures, and how to improve it. How memory functions: encoding (automatic versus effortful; semantic, visual, and acoustic), the self-reference effect, storage, and retrieval, plus the Atkinson-Shiffrin three-stage model, sensory memory, short-term memory and its capacity (Miller's 7 plus or minus 2), long-term memory, consolidation, elaborative rehearsal, explicit versus implicit memory (episodic, semantic, procedural), and recall, recognition, and relearning. Brain and memory: the amygdala, hippocampus, cerebellum, and prefrontal cortex, the engram, Lashley's equipotentiality hypothesis, arousal theory, flashbulb memory, the memory neurotransmitters, and Eric Kandel. Problems with memory: amnesia (anterograde and retrograde, the patient H.M.), Schacter's seven sins of memory, encoding failure, the Ebbinghaus forgetting curve, the Loftus misinformation effect, proactive and retroactive interference, and eyewitness misidentification. Enhancing memory: rehearsal, chunking, mnemonic devices (HOMES, PEMDAS), the self-reference study strategy, distributed practice, and sleep.
- Newton's Laws of Motion (Physics)Recall cards on Newton's laws of motion: force as a vector push or pull measured in newtons, external versus contact versus field forces, the four fundamental forces, and the net force as a vector sum; Newton's first law, inertia and its measure by mass, inertial reference frames, and equilibrium under zero net force; Newton's second law in scalar and vector form, F_net = m a and its momentum form F_net = dp/dt, with the proportionalities between force, mass, and acceleration; mass versus weight, w = m g, and how weight varies with local gravity while mass does not; Newton's third law and action-reaction pairs acting on different bodies, including thrust; common forces such as the normal force, tension, friction, Hooke's-law spring restoring force, and the real-versus-fictitious distinction; and how to draw and use free-body diagrams to apply Newton's second law.
- The Respiratory SystemRecall cards on the animal respiratory system: systems of gas exchange (why diffusion alone fails as body size grows, and the diversity of respiratory surfaces from skin and gills to insect tracheae and the mammalian airway from nasal cavity to alveoli); gas exchange across respiratory surfaces (partial pressure, the composition of air, and the oxygen and carbon dioxide partial-pressure gradients that drive diffusion in the lungs and tissues); breathing (Boyle's law and the mechanics of inhalation and exhalation, the pleurae, surfactant, lung compliance and resistance, restrictive and obstructive diseases, dead space, and gas exchange in amphibians and birds); and the transport of gases in bodily fluids (hemoglobin and cooperative oxygen binding, the oxygen-hemoglobin dissociation curve and what shifts it, the bicarbonate buffer system and chloride shift that carry carbon dioxide, and carbon monoxide poisoning).
- Emotion and Motivation (Psychology)Recall cards on what drives and moves us. Motivation: intrinsic versus extrinsic motivation, instinct theory, drive theory and homeostasis, arousal theory and the Yerkes-Dodson law, self-efficacy, Maslow's hierarchy of needs and self-actualization, and the social motives for achievement, affiliation, and intimacy. Hunger and eating: hunger pangs and glucose signaling, satiation and leptin, the hypothalamus, metabolic rate, set-point theory, the BMI thresholds for overweight, obese, and severely obese, obesity health risks, and the eating disorders anorexia nervosa, bulimia nervosa, and binge eating disorder. Sexual behavior: Kinsey and the Kinsey scale, Masters and Johnson's sexual response cycle and the refractory period, sexual orientation, and gender identity, transgender, cisgender, and gender dysphoria. Emotion: emotion versus mood, the James-Lange, Cannon-Bard, Schachter-Singer two-factor, and Lazarus cognitive-mediational theories, Ekman's seven universal emotions, the amygdala, hippocampus, and hypothalamus, the two fear paths, display rules, the facial feedback hypothesis, and the polygraph.
- Galaxies (Astronomy)Recall cards on galaxies beyond the Milky Way. Their discovery: Kant's island universes, the great debate over the spiral nebulae, and Edwin Hubble's 1924 proof, using cepheids in Andromeda, that galaxies lie far beyond our own. Their types on Hubble's tuning-fork diagram: Sa to Sc spirals and barred spirals, E0 to E7 ellipticals from dwarfs to giants, S0 lenticulars, and irregulars like the Magellanic Clouds, with their sizes, masses, and luminosities. Their properties measured from rotation and orbital speeds, and the mass-to-light ratios that betray dark matter. The extragalactic distance ladder: cepheids, type Ia supernovae, and the Tully-Fisher relation. And the expanding universe: Slipher's redshifts, Lemaitre's 1927 theory, the Hubble-Humason velocity-distance law, the Hubble constant, and the raisin-bread picture of expansion with no center.
- Introduction to Psychology (Psychology)Recall cards on the foundations of psychology. What is psychology: the scientific study of the mind and behavior, the scientific method, hypotheses and theories, and psychology as both a natural and a social science. The history of psychology: Wundt and the first laboratory, voluntarism and introspection, James and functionalism, Titchener and structuralism, Freud and psychoanalysis, Gestalt psychology, behaviorism, humanism, and the cognitive revolution. Contemporary psychology: the subfields from biopsychology and evolutionary psychology through developmental, personality, social, industrial-organizational, health, clinical, counseling, and forensic psychology. And careers in psychology: the PhD and the dissertation, the PsyD, master's-level careers, faculty roles, postdoctoral training, and licensure.
- The Milky Way Galaxy (Astronomy)Recall cards on our home galaxy. Its architecture: Herschel's and Shapley's mapping, the thin and thick disk, the nuclear bulge, and the stellar and dark-matter halo, with the Sun's place about 26,000 light-years from the center. Its spiral structure traced by the 21-cm hydrogen line, the Scutum-Centaurus and Perseus arms, and the Sun's Orion-Cygnus spur. Its mass from orbital speeds and Kepler's third law, the 225-million-year galactic year, and the evidence for a vast dark halo. Its center: the 4.6-million-solar-mass black hole Sagittarius A*, the stellar orbits that weigh it, and Andrea Ghez's Nobel-winning work. Its stellar populations: Baade's Population I and II and their ages and metallicities. And its formation and growth by protogalactic collapse and the ongoing accretion of dwarf galaxies, ending with the coming Andromeda merger.
- The Second Law of Thermodynamics (Physics)Recall cards on the second law of thermodynamics. Reversible and irreversible processes: the definition of each, why nearly all real processes are irreversible, the quasi-static and dissipation-free requirements for reversibility, free expansion and spontaneous heat flow as irreversible processes, and the microscopic origin of irreversibility. Heat engines: the working substance, hot and cold reservoirs, the zero internal-energy change over a cycle, net work W = Q_h - Q_c, and thermal efficiency e = W/Q_h = 1 - Q_c/Q_h. Refrigerators and heat pumps as reversed heat engines: Q_h = Q_c + W, the coefficients of performance K_R and K_P, and why a coefficient of performance can exceed 1. Statements of the second law: the Kelvin and Clausius statements, the impossibility of a perfect heat engine or perfect refrigerator, and the equivalence of the two statements. The Carnot cycle: its four reversible steps (two isothermal, two adiabatic), the Carnot engine, Q_c/Q_h = T_c/T_h, the efficiency e = 1 - T_c/T_h, Carnot's principle, the equal efficiency of all reversible engines, and the Carnot coefficients of performance. Entropy: delta-S = Q/T for a reversible isothermal step, the integral form, entropy as a state function, the zero net entropy change over a reversible cycle, the joule-per-kelvin unit, phase-change entropy, and the entropy statement that total entropy never decreases. Entropy on a microscopic scale: entropy as disorder, the statistical second law, delta-S = nR ln(V2/V1) for isothermal expansion, the third law, and the approach to perfect order at absolute zero.
- Electric Charges and Fields (Physics)Recall cards on electric charge and the electric field. Electric charge: its two types, like-repels-unlike-attracts, the coulomb unit, the elementary charge e = 1.602 x 10^-19 C, quantization, conservation, and the charged constituents of the atom, plus what makes an ion positive or negative. Conductors and insulators: conduction electrons and free charge flow, why excess charge spreads on a conductor, why charge stays put on an insulator, polarization, why a charged object attracts a neutral one, charging by induction, and grounding. Coulomb's law: F = k q1 q2 / r^2, its proportionalities, the permittivity of free space epsilon_0 = 8.85 x 10^-12, Coulomb's constant k = 8.99 x 10^9, the line of action, Newton's third law, and superposition. The electric field: E as force per unit positive charge with F = QE, the newton-per-coulomb unit, the field of a point charge, its direction, its independence from the test charge, and superposition. Continuous charge distributions: linear, surface, and volume charge densities, field by integration, and the uniform field sigma / (2 epsilon_0) of an infinite charged plane. Electric field lines: tangency, where they begin and end, line density and count, why they never cross, and that they are only a visualization. Electric dipoles: the definition, the dipole moment p = q d, the coulomb-meter unit, the zero net force and the torque tau = p x E in a uniform field, the alignment tendency, and permanent versus induced dipoles.
- Stars from Adolescence to Old Age (Astronomy)Recall cards on how stars age and die. Life on the main sequence: the zero-age main sequence, the small fraction of mass turned into energy by fusion, and how sharply lifetime depends on mass, from an O star lasting a million years to an M dwarf lasting hundreds of billions. The path off the main sequence: core contraction, shell hydrogen fusion, and the swelling into a cool, luminous red giant like Betelgeuse. Reading stellar ages off star clusters: the globular, open, and association types, and the main-sequence turnoff that dates a cluster and even limits the age of the universe. And the later stages: the triple-alpha process and helium flash, the layered carbon-oxygen core, the ejection of a planetary nebula, and, for massive stars, fusion up an onion-shell structure that ends at iron.
- Genes and ProteinsRecall cards on how genes are expressed as proteins: the genetic code (the central dogma, triplet codons, degeneracy, start and stop codons, reading frames and frameshifts, the Crick-Brenner experiment, the near-universal code); prokaryotic transcription (a single RNA polymerase, sigma factor and the holoenzyme, template versus coding strand, the -10 and -35 promoter consensus sequences, rho-dependent and intrinsic termination, polycistronic mRNA); eukaryotic transcription (three RNA polymerases, the TATA box and transcription factors, nucleosomes and the FACT complex); RNA processing (exons and introns, the 5' cap, the poly-A tail, splicing by spliceosomes, UTRs, tRNA anticodons); and translation (ribosome subunits, tRNA charging by aminoacyl-tRNA synthetases, the A, P, and E sites, prokaryotic and eukaryotic initiation, the Shine-Dalgarno sequence and Kozak's rules, peptidyl transferase, termination by release factors, signal sequences and chaperones).
- Harry PotterEnter the Wizarding World - spells, characters, and magic
- Alternating-Current Circuits (Physics)Recall cards on alternating-current circuits. AC sources: DC versus AC, the v = V0 sin(omega t) and i = I0 sin(omega t) forms, peak versus instantaneous notation, and US and European mains values. Simple AC circuits: the resistor in phase, the capacitor's current leading and the inductor's current lagging by pi/2, capacitive reactance XC = 1/(omega C), inductive reactance XL = omega L, their frequency dependence, and phasors. Series RLC circuits: impedance Z = sqrt(R^2 + (XL - XC)^2), the AC Ohm's law I0 = V0/Z, the phase angle, and the element voltages. Power: rms current and voltage, the average-power formulas, the power factor cos(phi), and why only resistors dissipate. Resonance: XL = XC, omega0 = 1/sqrt(LC), minimum impedance, maximum current and power, and the quality factor. Transformers: the voltage and current turns ratios, step-up and step-down, power conservation, and high-voltage transmission.
- MathematicsAlgebra, geometry, calculus, and number theory
- Thermodynamics (Chemistry)Recall cards on chemical thermodynamics: spontaneity (spontaneous and nonspontaneous processes, the independence of spontaneity from reaction speed, and the dispersal of matter and energy); entropy (the state function S, delta-S = q_rev/T, Boltzmann's S = k ln W and microstates, and how entropy varies with state of matter, phase change, temperature, and dissolution); the second and third laws (the entropy of the universe, delta-S_univ sign rules for spontaneity and equilibrium, the entropy change of the surroundings, and the zero entropy of a perfect crystal at 0 K); and Gibbs free energy (G = H - TS, delta-G = delta-H - T delta-S, the delta-G sign criterion, standard free energies of reaction and formation, delta-G = delta-G degree + RT ln Q, delta-G degree = -RT ln K, and the temperature dependence of spontaneity).
- Electromagnetic Induction (Physics)Recall cards on electromagnetic induction. Faraday's law: magnetic flux and the weber, the induced emf as the negative rate of change of flux, and the N-turn coil form. Lenz's law: the induced current opposes the flux change, the negative sign, the like-pole repulsion of an approaching magnet, and the energy-conservation basis. Motional emf: epsilon = Blv, the induced current and retarding force on a moving rod, and the mechanical-to-electrical power balance. Induced electric fields: the line-integral form of Faraday's law, the nonconservative character with no associated potential, and the field around a circular path. Eddy currents: magnetic damping, slotted plates, metal detectors, eddy-current braking, and induction cooktops. Electric generators and back emf: the rotating-coil emf, peak emf, motor-versus-generator energy conversion, and how back emf sets a motor's current. Applications: hard disk read heads, giant magnetoresistance, magnetic stripes, graphics tablets, regenerative braking, and transcranial magnetic stimulation.
- Stress, Lifestyle, and Health (Psychology)Recall cards on stress, health, and well-being. What stress is (a process of appraising events as overwhelming or threatening), health psychology, stimulus- versus response-based definitions, Selye's work, primary and secondary appraisal, eustress versus distress, Cannon's fight-or-flight response, the general adaptation syndrome (alarm, resistance, exhaustion), and the HPA axis and cortisol. Stressors: chronic versus acute, job strain, job burnout and its dimensions, and the Holmes-Rahe Social Readjustment Rating Scale. Stress and illness: psychophysiological disorders, psychoneuroimmunology, lymphocytes and immune suppression, cardiovascular disease, hypertension, Type A and Type B personality, asthma, and tension headaches. Regulation of stress: problem-focused versus emotion-focused coping, perceived control, social support, learned helplessness, exercise, and biofeedback. The pursuit of happiness: positive psychology, subjective well-being, Seligman's three components of a happy life, the income-happiness relationship, hedonic adaptation, flow, and positive affect.
- An Invisible World (Microbiology)Recall cards on the foundations of microbiology. What our ancestors knew: microbes and fermentation, ancient fermented foods, early ideas of contagion and immunity from Varro and Thucydides, Leeuwenhoek's animalcules, and the Golden Age of Microbiology with Pasteur and Koch. A systematic approach: taxonomy and classification, Linnaeus and Systema Naturae, the Linnaean hierarchy, binomial nomenclature, the kingdom systems of Haeckel and Whittaker, phylogenetic trees, Woese and Fox's rRNA three-domain system, horizontal gene transfer, and Bergey's Manuals. Types of microorganisms: the size scale from the unaided eye to viruses, the metric units of length, and the defining features of bacteria, archaea, protists, fungi, helminths, and viruses, along with the subfields that study them.
- Demand and Supply (Economics)Recall cards on how markets set prices. Demand and the law of demand (price and quantity demanded move inversely), supply and the law of supply (they move together), demand and supply schedules and curves, and market equilibrium where the two curves cross. Surpluses (excess supply above equilibrium) and shortages (excess demand below equilibrium) and how prices adjust back. Movements along a curve versus shifts of the whole curve: normal and inferior goods, substitutes and complements, ceteris paribus, and the factors that shift demand and supply. The four-step process for analyzing how an event changes equilibrium, and the outcomes of demand and supply shifts. Price controls: binding price ceilings and floors, with rent control and the minimum wage as examples. Efficiency: consumer surplus, producer surplus, social (total) surplus, and the deadweight loss created when a market produces at an inefficient quantity.
- Equilibria of Other Reaction Classes (Chemistry)Recall cards on solubility and other equilibria beyond simple acid-base systems: precipitation and dissolution (the solubility product constant Ksp, molar solubility, saturated, unsaturated, and supersaturated solutions, the ion product Qsp and its comparison with Ksp to predict precipitation, the common ion effect, selective precipitation, and pH-controlled solubility); Lewis acids and bases (electron-pair donors and acceptors, coordinate covalent bonds, acid-base adducts, complex ions and their ligands, and the formation constant Kf); and coupled equilibria (shared species linking two equilibria, the product-of-K rule, acid-enhanced solubility of basic-anion salts, and complex-ion driven dissolution), with applications including ocean acidification of calcium carbonate and the fluoridation of tooth enamel.
- Photons and Matter Waves (Physics)Recall cards on the birth of quantum physics. Blackbody radiation, the Stefan-Boltzmann law P = sigma*A*T^4, Wien's displacement law, the ultraviolet catastrophe, and Planck's quantization E_n = n*h*f. The photoelectric effect and Einstein's photon explanation, the photoelectric equation K_max = h*f - phi, the work function, and the cutoff frequency. The Compton effect and the photon momentum p = h/lambda. Bohr's model of the hydrogen atom, the Rydberg formula, quantized angular momentum, the Bohr radius, and the energy levels E_n = -13.6 eV/n^2. De Broglie's matter waves lambda = h/p and the Davisson-Germer experiment. Wave-particle duality and Heisenberg's uncertainty principle Delta x * Delta p >= h-bar/2.
- Motion Along a Straight Line (Physics)Recall cards on one-dimensional kinematics: position and frame of reference; displacement as the change in position (final minus initial), a vector measured in meters, and its distinction from distance traveled; average velocity as displacement over elapsed time; instantaneous velocity as the time derivative of position and the slope of a position-versus-time graph; speed as a scalar and instantaneous speed as the magnitude of velocity; average and instantaneous acceleration as the rate of change of velocity and the slope of a velocity-versus-time graph, with the sign conventions relating acceleration and velocity direction to speeding up or slowing down; the constant-acceleration kinematic equations and the notation behind them; free fall under gravity alone with acceleration g directed downward; and finding velocity and displacement by integrating acceleration and velocity over time.
- Sources of Magnetic Fields (Physics)Recall cards on the sources of magnetic fields. The Biot-Savart law: the field of a current element, the permeability of free space, the right-hand rule for the direction, and the field of a circular arc and a full loop. The magnetic field of a thin straight wire: B = mu_0 I/(2 pi R), concentric circular field lines, and the right-hand rule. The force between two parallel currents: attraction and repulsion, the historical ampere definition, and the pinch effect. The magnetic field of a current loop: the magnetic dipole moment, the on-axis field, and the inverse-cube dipole falloff. Ampere's law: the line integral of B, the enclosed current, the Amperian loop, when to use it versus the Biot-Savart law, and the field inside and outside a thick wire. Solenoids and toroids: the uniform interior field of a solenoid, the zero exterior field, and the toroid field. Magnetism in matter: atomic dipole moments, paramagnetism, diamagnetism, ferromagnetism, magnetic domains, hysteresis, susceptibility, and permeability.
- Celestial Distances (Astronomy)Recall cards on how astronomers measure distances in space. Fundamental units: the history of the meter, the light-second, and the astronomical unit (the average Earth-Sun distance), pinned down in modern times by radar ranging. Surveying the stars: parallax and triangulation, the parsec, the relation D = 1/p, the first stellar parallax measured by Bessel in 1838, and the Hipparcos and Gaia satellites that extended the method across the Galaxy. Variable stars as standard candles: pulsating cepheids and RR Lyrae stars, the light curve and period, and Henrietta Leavitt's period-luminosity relation that let cepheids reach tens of millions of light-years. And the H-R diagram method (spectroscopic parallax), the luminosity classes from supergiants to dwarfs, and the cosmic distance ladder that chains all these techniques together.
- DNA Structure and FunctionRecall cards on DNA structure and function: the historical experiments identifying DNA as the genetic material (Miescher, Griffith, Avery-MacLeod-McCarty, Hershey-Chase, Chargaff), the structure of the double helix (nucleotides, purines and pyrimidines, base pairing, antiparallel strands, phosphodiester bonds, helix dimensions), DNA packaging (supercoiling, nucleosomes, heterochromatin and euchromatin), sequencing and gel electrophoresis, the semi-conservative model and the Meselson-Stahl experiment, DNA replication in prokaryotes and eukaryotes (origins, forks, helicase, primase, polymerases, leading and lagging strands, Okazaki fragments, telomeres and telomerase), and DNA repair and mutation types.
- Introduction (Astronomy)Recall cards introducing astronomy. What astronomy studies and where the elements of life were made. The nature of science: hypotheses, observational versus historical science, and peer review. The universality of physical laws. Numbers in astronomy: scientific notation, the speed of light, and the light-year. Light travel time and looking back in time. A tour of the solar system: planets, stars, the astronomical unit, and the sizes and distances of the Earth, Moon, and Sun. The Milky Way and the large-scale universe: galaxies, constellations, the Local Group, Andromeda, superclusters, and quasars. The universe of the very small: atoms, molecules, elements, and the density of matter in air, interstellar, and intergalactic space. Carl Sagan's cosmic calendar.
- Static Equilibrium and Elasticity (Physics)Recall cards on the static equilibrium of rigid bodies and on stress, strain, and elasticity. Static equilibrium requires zero linear and zero angular acceleration: the first condition sets the vector sum of external forces to zero (translational equilibrium), and the second sets the sum of external torques about any axis to zero (rotational equilibrium), both at once. For rotation about a fixed z-axis the six scalar equations reduce to three, torque magnitude is r F sin(theta), the pivot may be chosen freely, and weight acts at the center of gravity. Solving equilibrium problems: free-body diagrams with forces at their real points of application, choosing the pivot to cancel an unknown, statically indeterminate cases, and the normal, friction, tension, and hinge forces involved. Stress is force per unit area and strain is the dimensionless fractional deformation; within the linear limit stress = elastic modulus times strain, measured in pascals. Tensile, compressive, bulk, and shear stress and strain define Young's modulus, the bulk modulus, and the shear modulus. Elasticity, the proportionality and elastic limits, Hooke's law, the plastic region, permanent deformation, and the fracture (breaking) stress.
- Atomic Structure (Physics)Recall cards on the quantum structure of atoms. The hydrogen atom and its three quantum numbers n, l, and m, the quantized energy E_n = -13.6 eV/n^2, orbital angular momentum L = sqrt(l(l+1)) h-bar, space quantization, and spectroscopic s, p, d, f notation. The orbital magnetic dipole moment, the Bohr magneton, and the Zeeman effect. Electron spin with s = 1/2, the Stern-Gerlach experiment, the Pauli exclusion principle and the building-up of the periodic table. Atomic spectra and selection rules, characteristic X-rays and Moseley's law, bremsstrahlung, and the physics of lasers including stimulated emission, population inversion, and gain media.
- Diffraction (Physics)Recall cards on the diffraction of light. Single-slit diffraction: the bright central maximum and dimmer secondary maxima, the dark-fringe condition a sin(theta) = m*lambda, and why a narrower slit spreads the pattern. Intensity in single-slit diffraction: the phasor derivation, I = I0 (sin(beta)/beta)^2 with beta = (pi a sin(theta))/lambda, and the faint 0.045 and 0.016 secondary maxima. Double-slit diffraction as an interference pattern under a single-slit envelope, and missing orders. Diffraction gratings: d sin(theta) = m*lambda, sharp principal maxima, and spectroscopy. Circular apertures and resolution: the Rayleigh criterion theta = 1.22 lambda/D, microscope resolution x = 0.61 lambda/NA, and the diffraction limit. X-ray diffraction and Bragg's law m*lambda = 2d sin(theta). Holography: recording amplitude and phase by the interference of laser light.
- Gene ExpressionRecall cards on how cells regulate gene expression: the levels of regulation (why cells regulate, prokaryotic versus eukaryotic control, the five eukaryotic stages); prokaryotic operons (the trp and lac operons, repressors, activators and inducers, corepressors, cAMP and the catabolite activator protein, inducible versus repressible control); eukaryotic epigenetic regulation (nucleosomes, chromatin remodeling, histone modification, DNA methylation and CpG islands, imprinting); eukaryotic transcriptional control (general and specific transcription factors, the TATA, CAAT and GC boxes, enhancers and DNA bending); post-transcriptional control (alternative splicing, mRNA stability and UTRs, microRNAs, Dicer and RISC); translational and post-translational control (the eIF-2 switch, cap-poly-A looping, protein modification, ubiquitin and the proteasome); and cancer as a disease of altered gene expression (tumor-suppressor genes, p53, proto-oncogenes and oncogenes, cancer epigenetics, and gene-expression-targeted therapies).
- Observing the Sky: The Birth of Astronomy (Astronomy)Recall cards on how humans learned to read and understand the sky. The celestial sphere and its landmarks: zenith, horizon, celestial poles and equator, and how the pole's altitude reveals your latitude. The ecliptic, the 88 constellations, asterisms, and the zodiac. Ancient astronomy: Eratosthenes measuring the Earth, Hipparchus and his star catalog, magnitudes, and precession, Ptolemy's geocentric model and the Almagest, Stonehenge, and the Maya. Astrology versus astronomy: horoscopes, the twelve signs, and why astrology has no scientific support. The birth of modern astronomy: Copernicus and the heliocentric model, and Galileo's telescopic discoveries of the phases of Venus, the moons of Jupiter, the stars of the Milky Way, and the mountains of the Moon.
- Quantum Mechanics (Physics)Recall cards on nonrelativistic quantum mechanics. The wave function and the Born interpretation |Psi|^2 as a probability density, normalization, expectation values, and the position and momentum operators. The Heisenberg uncertainty principle in its position-momentum and energy-time forms. The time-dependent and time-independent Schrodinger equations, stationary states, and separation of variables. The quantum particle in a box with quantized energies E_n = n^2 pi^2 h-bar^2/(2mL^2) and zero-point energy. The quantum harmonic oscillator with evenly spaced levels E_n = (n + 1/2) h-bar omega. Quantum tunneling through potential barriers, the transmission probability, and applications from alpha decay to the scanning tunneling microscope.
- Same yearWhat else happened in that year?
- Fixed-Axis Rotation (Physics)Recall cards on the rotation of a rigid body about a fixed axis. Rotational variables: angular position theta = s/r in radians, angular displacement, angular velocity omega = d theta/dt, and angular acceleration alpha = d omega/dt, with the counterclockwise-positive sign convention and the right-hand rule for the direction of the angular velocity vector. Rotation with constant angular acceleration: the four rotational kinematic equations as direct analogs of the linear ones (theta for x, omega for v, alpha for a). Relating angular and translational quantities: tangential speed v_t = r omega, tangential acceleration a_t = r alpha, centripetal acceleration a_c = r omega^2, and the total linear acceleration. Moment of inertia and rotational kinetic energy: K = (1/2) I omega^2, I = sum m r^2 as the rotational analog of mass, and its dependence on the axis and the mass distribution. Calculating moments of inertia: the integral I = integral r^2 dm, the parallel-axis theorem I = I_cm + m d^2, and standard results for a rod (about center and end), a disk, and compound bodies. Torque tau = r x F, its magnitude r F sin theta, the lever arm, net torque, and its sign. Newton's second law for rotation, sum tau = I alpha, the rotational analog of F = ma. And work and power for rotational motion, W = integral tau d theta, the work-energy theorem, and P = tau omega.
- Motion in Two and Three Dimensions (Physics)Recall cards on kinematics in two and three dimensions: the position, displacement, and velocity vectors in unit-vector notation and their component forms; instantaneous velocity as the derivative of position and always tangent to the path; the acceleration vector as the first derivative of velocity and the second derivative of position; the independence of motion along perpendicular axes and the constant-acceleration equations applied per axis; projectile motion with zero horizontal acceleration and downward gravity, including the launch components, time of flight, maximum height, range, the 45-degree maximum, complementary launch angles, and the parabolic trajectory; uniform and nonuniform circular motion, centripetal acceleration expressed through speed, period, and angular frequency, and tangential and total acceleration; and relative motion, with the addition rules for position, velocity, and acceleration across reference frames and the invariance of acceleration between frames moving at constant relative velocity.
- Potential Energy and Conservation of Energy (Physics)Recall cards on potential energy and the conservation of energy: potential energy as energy stored in a system because of the configuration of its interacting objects, the rule that the change in potential energy is the negative of the work done by the associated conservative force, the arbitrary additive constant and the choice of a zero reference, gravitational potential energy U = mgy near Earth's surface, and elastic potential energy U = (1/2)kx^2 for a spring. Conservative forces (path-independent work, zero work around a closed path) versus non-conservative dissipative forces such as friction and air resistance, recovering a conservative force from its potential energy by F = -dU/dx or the gradient, and the curl test. Mechanical energy E = K + U, its conservation when only conservative forces do work, W_nc = change in E when they do not, and the law of conservation of energy. Potential energy diagrams: the total-energy line, the condition K = E - U >= 0, turning points, allowed and forbidden regions, force as minus the slope, equilibrium points, stable versus unstable equilibria from the second derivative, maximum speed at a potential minimum, and the infinite potential well. And sources of energy: thermal, chemical, radiant, and nuclear energy, renewable versus nonrenewable sources, conversion losses, hydro, wind, and solar power, and the 2010 world energy shares.
- Inductance (Physics)Recall cards on inductance. Mutual inductance: the henry, the M = N Phi / I definition, its symmetry and geometry dependence, and the induced emf epsilon = -M dI/dt. Self-inductance: Phi = LI, the self-induced emf -L dI/dt, its Lenz's-law polarity, the inductor as a circuit element, and the solenoid formula. Energy in a magnetic field: U = (1/2) L I^2, the energy density B^2/(2 mu0), and inductor power. RL circuits: the asymptotic rise and decay of current, the time constant L/R, the 63% rule, and the initial and steady-state conditions. LC oscillations: omega = 1/sqrt(LC), the electric-to-magnetic energy exchange, the charge and current solutions and their 90-degree phase, and the mass-spring analogy. RLC series circuits: damped oscillations, the governing differential equation, and the underdamped, critically damped, and overdamped regimes.
- Phylogenies and the History of LifeRecall cards on phylogeny and the history of life: organizing life on Earth (phylogeny and phylogenetic trees, taxonomy and systematics, the Linnaean hierarchy, the three domains, binomial nomenclature, and the parts of a tree, including rooted and unrooted trees, nodes, basal and sister taxa, polytomies, and what branch length does and does not mean); determining evolutionary relationships (homologous versus analogous structures and homoplasies, molecular systematics, cladistics and clades, shared ancestral versus shared derived characters, and maximum parsimony); and perspectives on the phylogenetic tree (horizontal gene transfer and its mechanisms, gene transfer agents, HGT in prokaryotes and eukaryotes, and alternative models of early evolution, including the web-of-life, ring-of-life, endosymbiont, and genome-fusion models).
- Roman EmperorsThe rulers of ancient Rome
- Work and Kinetic Energy (Physics)Recall cards on work and kinetic energy: work as the transfer of energy when a force acts through a displacement, the infinitesimal work dW = F.dr, the constant-force result W = Fd cos(theta), the parallel-component rule, work as a line integral or the area under a force-versus-displacement curve, the sign of work, the joule and foot-pound, and the work done by friction, gravity, and a spring, including conservative versus dissipative forces and the zero work around a closed path. Kinetic energy K = (1/2)mv^2 as a non-negative scalar that depends on speed and reference frame, its joule unit, the momentum form K = p^2/(2m), and translational versus rotational kinetic energy. The work-energy theorem W_net = K_f - K_i derived from Newton's second law, its use for variable forces and curved frictionless paths, and the consequences of positive, negative, and zero net work. And power as the rate of doing work, average power W/t, instantaneous power dW/dt = F.v, the watt, and the horsepower.
- CelebritiesFamous people, actors, musicians, athletes, and pop culture icons
- Composition of Substances and Solutions (Chemistry)Recall cards on the composition of substances and solutions: formula mass and the mole concept (formula versus molecular mass; the mole and Avogadro's number; molar mass and mass-mole-entity conversions); determining empirical and molecular formulas (percent composition; deriving an empirical formula from element masses or percent composition; the whole-number multiple linking empirical and molecular formulas); molarity (solution, solvent, solute, and aqueous solution; concentration; molarity and its unit; dilution and the dilution equation); and other units for solution concentrations (mass percentage, volume percentage, mass-volume percent, parts per million, and parts per billion).
- Gauss's Law (Physics)Recall cards on electric flux and Gauss's law. Electric flux: what it measures, its definition as the dot product of the electric field with an area vector, the symbol Phi, the unit N*m^2/C, its scalar nature, the area vector of flat and closed surfaces, the E*A*cos(theta) form for a uniform field, when flux is maximum or zero, the surface-integral form for a nonuniform field, the exit-positive/enter-negative sign convention, and why the net flux through a surface enclosing no charge is zero. Gauss's law: the statement that net flux equals enclosed charge over epsilon_0, its integral form, the meaning of q_enc, the Gaussian surface, that E is the total field from all charges, why outside charges add zero net flux, why the flux is independent of surface shape, the equivalence to Coulomb's law, the point-charge sphere result, and the role of superposition. Applying Gauss's law: identifying symmetry, matching the Gaussian surface to it, the spherical, cylindrical, and planar symmetry cases, and the field results for a sphere inside and out, an infinite line E = lambda/(2*pi*epsilon_0*r), an infinite plane E = sigma/(2*epsilon_0), parallel plates, and a spherical shell. Conductors in electrostatic equilibrium: the definition, conduction electrons, why the interior field is zero, why excess charge sits on the outer surface, the perpendicular field just outside E = sigma/epsilon_0, cavity induction, charge concentration at sharp points, and electrostatic shielding.
- Interference (Physics)Recall cards on the wave interference of light. Young's double-slit experiment: coherence versus incoherence, constructive and destructive interference, fringes, and the historical evidence for the wave nature of light. The mathematics of interference: path length difference delta-l = d sin(theta), bright fringes at d sin(theta) = m*lambda, dark fringes at d sin(theta) = (m + 1/2)*lambda, order m, and the fringe position y_m = m*lambda*D/d. Multiple-slit interference: principal maxima, the N minus 2 secondary maxima, secondary-maximum amplitude 1/N and intensity 1/N^2, and the diffraction grating. Interference in thin films: the 180-degree phase change on reflection off a higher-index medium, the in-film wavelength lambda_n = lambda/n, and the soap-film constructive and destructive conditions. The Michelson interferometer: the beam splitter, the fringe-shift relation 2*delta-d = m*lambda_0, the compensator plate, and its use in precision measurement.
- Poverty and Economic Inequality (Economics)Recall cards on poverty and economic inequality. Drawing the poverty line: how poverty is measured, Orshansky's original method, and U.S. poverty rates by group. The poverty trap: how declining benefits blunt the incentive to work. The safety net: TANF, the earned income tax credit, SNAP, Medicaid, WIC, and Supplemental Security Income. Measuring and explaining income inequality: quintiles, the Lorenz curve, household structure, education, and winner-take-all labor markets. Government policies to reduce inequality: redistribution, progressive taxes, the estate tax, ladders of opportunity, and the equality-output tradeoff.
- Capacitance (Physics)Recall cards on capacitors and capacitance. Capacitors and capacitance: what a capacitor is and stores, its two-conductor construction, the definition C = Q/V, the farad and its name, the practical range, geometry dependence, the constant Q/V ratio, the parallel-plate result C = eps0*A/d, the permittivity of free space, the field E = sigma/eps0, and the spherical, isolated-sphere, and cylindrical capacitance formulas. Capacitors in series and parallel: the reciprocal-sum series rule, equal series charge, the smaller-than-smallest result, series voltage adding, the parallel sum rule, equal parallel voltage, the larger-than-largest result, parallel charge adding, and network reduction. Energy stored: field storage, the three energy forms U = 1/2 C V^2, U = Q^2/2C, U = 1/2 Q V, energy persisting after disconnection, the energy density u = 1/2 eps0 E^2, and the defibrillator. Capacitor with a dielectric: what a dielectric is, the dielectric constant kappa, kappa = 1 for vacuum and kappa > 1 otherwise, C = kappa*C_0, the constant-charge and voltage/energy drops on a disconnected capacitor, dielectric strength, and the stud finder. Molecular model of a dielectric: polar versus nonpolar molecules, alignment and induced dipoles, surface induced charge, the opposing induced field, E = E_0/kappa, and breakdown.
- Life in the Universe (Astronomy)Recall cards on the search for life beyond Earth. The cosmic context: the chemical evolution of the elements, organic molecules and hydrocarbons, biochemistry, and Earth as the third planet with liquid water. Astrobiology: the elements and solvent life requires, extremophiles and the known limits of temperature, acidity, and alkalinity, the earliest fossils and stromatolites, the rise of oxygen, proteins and DNA, the RNA world, and the Miller-Urey experiments. Searching the solar system and beyond: the habitable zone, the Viking, Curiosity, and Perseverance missions to Mars, the subsurface oceans of Europa and Enceladus, the hydrocarbon lakes and tholins of Titan, the first exoplanet, and atmospheric biosignatures. And the search for extraterrestrial intelligence: the Drake equation, why radio waves are favored, Project Ozma, the Allen Telescope Array, Arecibo, FAST, and Breakthrough Listen.
- Relativity (Physics)Recall cards on special relativity. Einstein's two postulates: the laws of physics are the same in all inertial frames, and light travels at the same speed c in all inertial frames regardless of the motion of source or observer. Relativity of simultaneity. Time dilation Delta t = gamma * Delta tau, proper time, and the Lorentz factor gamma = 1/sqrt(1 - v^2/c^2). The twin paradox. Length contraction L = L0*sqrt(1 - v^2/c^2) along the direction of motion. The Lorentz transformation, the invariant spacetime interval, and light cones. Relativistic velocity addition. The relativistic Doppler effect, redshift, and blueshift. Relativistic momentum p = gamma*m*u. Relativistic energy E = gamma*m*c^2, rest energy E0 = m*c^2, kinetic energy K = (gamma - 1)*m*c^2, the energy-momentum relation E^2 = (pc)^2 + (mc^2)^2, and mass-energy equivalence.
- The Stars: A Celestial Census (Astronomy)Recall cards on taking a census of the stars. The solar neighborhood: counting the stars within about 21 light-years shows that cool, faint red M dwarfs vastly outnumber luminous stars, and that the bright stars in our sky are bright because they are powerful, not because they are near. Masses: how binary stars and Newton's form of Kepler's third law let astronomers weigh stars, from the smallest true stars near 1/12 of a solar mass, through brown dwarfs, up to about 250 solar masses, and the mass-luminosity relation linking the two. Diameters: the indirect methods (lunar occultations, eclipsing binaries, and the Stefan-Boltzmann law) that reveal sizes from roughly Sun-sized up to the vast red supergiant Betelgeuse. And the Hertzsprung-Russell diagram: the plot of luminosity against temperature on which the main sequence, giants, supergiants, and white dwarfs each take their place.
- Angular Momentum (Physics)Recall cards on angular momentum and rolling motion. Rolling without slipping: the contact point is instantaneously at rest, v_CM = R omega, a_CM = R alpha, and d_CM = R theta; the acceleration down an incline a_CM = m g sin(theta)/(m + I_CM/r^2), the static-friction bound needed to prevent slipping, and the split of kinetic energy into translational (1/2) m v_CM^2 plus rotational (1/2) I_CM omega^2 with friction doing no work. Angular momentum of a particle: l = r x p, magnitude r p sin(theta), direction by the right-hand rule, the lever-arm form l = r_perp m v, and the unit kg m^2/s. The rotational form of Newton's second law, sum tau = dl/dt, and for a system sum tau_ext = dL/dt. Angular momentum of a rigid body, L = I omega, directed along the rotation axis. Conservation of angular momentum when the net external torque is zero: I omega = I' omega', the ice-skater effect, and the rise in rotational kinetic energy K'_rot = K_rot (I/I'). And the precession of a gyroscope: gravitational torque tau = r M g sin(theta) perpendicular to L, the precession rate omega_p = r M g/(I omega), nutation, and Earth's 26,000-year precession.
- Linear Momentum and Collisions (Physics)Recall cards on linear momentum and collisions: linear momentum p = mv as a vector pointing along the velocity, measured in kg·m/s, characterizing an object's quantity of motion and depending linearly on mass and velocity. Impulse J as force times time, the infinitesimal and integral forms, the impulse-momentum theorem J = delta p, Newton's second law as F = dp/dt, and the average force in a collision. Conservation of linear momentum for a closed system, why internal Newton's-third-law pairs cancel while external forces change total momentum. Types of collisions: momentum always conserved, kinetic energy conserved only in elastic collisions, inelastic and perfectly inelastic collisions, and explosions. Collisions in multiple dimensions with per-direction conservation and component equations. The center of mass as the weighted average position of mass, r_CM and its component and integral forms, F_ext = M a_CM, and the constant center-of-mass velocity of a system with zero external force. And rocket propulsion as a variable-mass system, exhaust velocity, the Tsiolkovsky rocket equation delta v = u ln(m_0/m), and the effect of gravity on a launch.
- The Sun: A Nuclear Powerhouse (Astronomy)Recall cards on how the Sun actually shines. The nineteenth-century puzzle of the Sun's energy source: chemical burning would last only a few thousand years, and even Kelvin and Helmholtz's gravitational contraction could power it for only about 100 million years, far short of Earth's geological age. The answer came from Einstein's E = mc^2 and nuclear fusion: deep in the core, above about 12 million K, the proton-proton chain fuses roughly 600 million tons of hydrogen into helium each second, converting about 4 million tons of matter into pure energy. The solar interior in theory: hydrostatic equilibrium, the radiative and convective zones, and the hundreds of thousands of years a photon takes to escape while a neutrino leaves in seconds. And the observations that confirm it: the solar neutrino problem, neutrino oscillation, the Davis and Sudbury experiments, and helioseismology.
- Mendel's Experiments and HeredityRecall cards on Mendelian genetics: Gregor Mendel's pea experiments, true-breeding lines, the P/F1/F2 generations, dominant and recessive traits, genotype and phenotype, alleles and loci, homozygous and heterozygous, the 3:1 and 1:2:1 ratios, Punnett squares and test crosses, incomplete dominance, codominance, multiple alleles, lethal and X-linked alleles, the laws of dominance, segregation, and independent assortment, dihybrid 9:3:3:1 crosses, linkage and recombination, and epistasis.
- The Evolution of PopulationsRecall cards on population genetics and adaptive evolution: population evolution (population genetics, the modern synthesis, microevolution versus macroevolution, populations evolve while individuals do not, allele and genotype frequencies, the gene pool, the Hardy-Weinberg principle and its equations and equilibrium assumptions); population genetics forces (genetic and phenotypic variation, heritability, genetic drift, the bottleneck and founder effects, gene flow, mutation, nonrandom and assortative mating, inbreeding and inbreeding depression, clines and geographic variation); and adaptive evolution (fitness and relative fitness, stabilizing, directional, and diversifying selection, frequency-dependent selection, sexual dimorphism and sexual selection, the handicap principle and good genes hypothesis, and the constraints that keep selection from producing a perfect organism).
- Labor Markets and Income (Economics)Recall cards on labor markets and income. The theory of labor markets: marginal productivity, the value of the marginal product, marginal revenue product, and how wages and employment are set in competition. Imperfect competition: monopsony, the marginal cost of labor, and its effect on wages and jobs. Supply-side market power: labor unions, collective bargaining, and their wage and employment effects. Bilateral monopoly. Employment discrimination: labor market discrimination, Gary Becker's argument, U.S. wage gaps by race and gender, and the Equal Pay, Civil Rights, and Age Discrimination in Employment Acts. Immigration and its effects on wages, the economy, and taxes.
- Production, Costs, and Industry Structure (Economics)Recall cards on how firms produce and what it costs. Explicit versus implicit costs, and accounting profit versus economic profit. The short-run production function: fixed and variable inputs, marginal product, and the law of diminishing marginal product. Short-run costs: fixed, variable, total, and marginal cost, the average cost measures, and the shapes of the U-shaped average total cost curve and the marginal cost curve that cuts it at its minimum. Then the long run, where all inputs vary: the long-run average cost curve built from short-run curves, and how economies of scale, constant returns, and diseconomies of scale, read against market demand, shape an industry's structure.
- Welcome to Economics! (Economics)Recall cards introducing economics. The core problem of scarcity: economics as the study of decision-making under scarcity, limited resources, and time as the ultimate scarce resource. The division of labor (Adam Smith, The Wealth of Nations, 1776; the pin factory), and why it raises production: comparative advantage, faster and higher-quality specialists, and economies of scale; specialization requires trade. The two branches of the field: microeconomics (individual agents) versus macroeconomics (the economy as a whole), the goals of macroeconomic policy, and monetary versus fiscal policy. How economists think: Keynes on economics as a method, theories versus models, and the circular flow diagram of households and firms in the goods-and-services and labor markets. How economies are organized: traditional, command, and market systems, private enterprise, globalization, exports and imports, GDP, and the rising ratio of exports to GDP.
- Cell CommunicationRecall cards on how cells signal to one another and respond: types of chemical signaling (paracrine, endocrine, autocrine, direct), internal and cell-surface receptors, signal transduction and second messengers, the cellular response, and signaling in single-celled organisms.
- Modern Understanding of InheritanceRecall cards on the chromosomal basis of heredity: the chromosomal theory of inheritance (Boveri, Sutton, Carothers, Morgan), genetic linkage, crossing over and chiasmata, parental versus recombinant offspring, recombination frequency, genetic maps and centimorgans, three-point crosses, karyotypes and karyograms, nondisjunction, aneuploidy (monosomy and trisomy including Down syndrome), sex-chromosome variations (triplo-X, Klinefelter, Turner) and X inactivation, polyploidy, and chromosome structure changes (duplications, deletions, inversions, translocations).
- Monopolistic Competition and Oligopoly (Economics)Recall cards on the two intermediate market structures between perfect competition and monopoly. Monopolistic competition: many firms competing with differentiated products, how differentiation by physical features, location, intangibles, and perception gives each firm a mini-monopoly, short-run profit or loss versus long-run zero economic profit through entry and exit, allocative and productive inefficiency with excess capacity, the offsetting benefit of product variety, and the role of advertising. Oligopoly: a few large firms with mutual interdependence, barriers to entry and economies of scale, collusion, cartels, and tacit collusion, the prisoner's dilemma and dominant strategies, the kinked demand curve, and the lysine price-fixing case.
- Elasticity (Economics)Recall cards on elasticity, the measure of how responsive quantity is to price. Price elasticity of demand and of supply as ratios of percentage changes, why the demand elasticity is negative but reported as an absolute value, and the elastic (greater than 1), unitary (equal to 1), and inelastic (less than 1) ranges. The midpoint method and why it gives the same value whether price rises or falls, and how elasticity differs from slope. The polar cases: perfectly elastic (a horizontal line), perfectly inelastic (a vertical line), and constant unitary elasticity. How elasticity determines who bears a tax and how a price change moves total revenue when demand is elastic, inelastic, or unitary, plus the short-run versus long-run difference. Finally, elasticity beyond price: income elasticity and normal versus inferior goods, cross-price elasticity and substitutes versus complements, and the wage and savings elasticities.
- Labor and Financial Markets (Economics)Recall cards applying demand and supply to two special markets. In the labor market employers demand labor, workers supply it, and the wage is the price: the law of demand and supply, the equilibrium wage, and how a wage above or below equilibrium creates unemployment or a labor shortage. Derived demand and the factors that shift labor demand and labor supply. The minimum wage as a price floor, the living wage, and when a minimum wage is non-binding. In the financial market savers supply financial capital, borrowers demand it, and the interest rate is the price: the rate of return, equilibrium, excess supply and excess demand, the factors that shift the supply of financial capital, and usury laws as a price ceiling. Finally, the market system as an information mechanism: how prices collect and transmit information about scarcity and profitability so that consumers and producers respond appropriately without any central authority and without knowing the cause, and how price controls distort that information.
- Perfect Competition (Economics)Recall cards on the perfectly competitive market: many firms selling identical products, full information, and free entry and exit, with each firm a price taker facing a perfectly elastic demand curve. How a competitive firm chooses output where marginal revenue equals marginal cost (and price equals marginal cost), when it earns a profit, breaks even, or takes a loss against average total cost, and the shutdown point at minimum average variable cost that makes its marginal cost curve its short-run supply curve. Then the long run: how entry and exit drive economic profits to zero at minimum average total cost, the constant, increasing, and decreasing cost industries behind the long-run supply curve, and why the outcome is both productively and allocatively efficient.
- Cell ReproductionRecall cards on how cells reproduce: genomes and chromosome structure, DNA compaction, the cell cycle (interphase and mitosis), cytokinesis in animals and plants, cell-cycle checkpoints and their positive and negative regulators, cancer, and prokaryotic binary fission.
- Monopoly and Antitrust Policy (Economics)Recall cards on how governments limit market power. Corporate mergers: vertical, conglomerate, and horizontal combinations, acquisitions, FTC notification thresholds, and the Sherman, Clayton, and Celler-Kefauver antitrust laws. Measuring concentration: the four-firm concentration ratio and the Herfindahl-Hirschman Index (HHI), and why regulators now favor detailed market analysis. Regulating anticompetitive behavior: price fixing, bid rigging, market division, restrictive practices such as exclusive dealing, tie-in sales, bundling, and predatory pricing, with the vitamin and Microsoft cases. Regulating natural monopolies: cost-plus versus price cap regulation and marginal-cost pricing losses. The great deregulation experiment: regulatory capture and the airline case.
- Environmental Protection and Negative Externalities (Economics)Recall cards on the economics of pollution and environmental policy. Externalities: positive and negative spillovers, social versus private costs, and why a negative externality causes market failure and shifts the supply curve. Command-and-control regulation: allowable-quantity and technology mandates, their inflexibility and weak incentives, and the EPA, Clean Air Act, and Clean Water Act. Market-oriented tools: pollution charges, marketable permits, cap-and-trade, and Coase's property-rights insight. Benefits and costs: the marginal benefit and marginal cost of pollution reduction and the economically optimal level. International issues: cross-border externalities, global warming, and biodiversity. The output-versus-environment production possibilities frontier tradeoff.
- Cellular RespirationRecall cards on how cells extract energy from glucose: redox and electron carriers, glycolysis, the citric acid cycle, oxidative phosphorylation, fermentation, and regulation.
- Choice in a World of Scarcity (Economics)Recall cards on how scarcity forces choice. The budget constraint: the combinations of two goods a consumer can afford (the Alphonso burgers-and-bus-tickets example), opportunity cost as the next best alternative given up, the slope of the budget line, marginal analysis, the law of diminishing marginal utility, utility maximization, and why sunk costs should not affect current decisions. The production possibilities frontier (PPF): attainable versus unattainable points, productive and allocative efficiency, the law of increasing opportunity cost, why the PPF bows outward, and comparative advantage. Confronting objections to the economic approach: positive versus normative statements, the self-interest assumption and Adam Smith's caveat, and economics as a descriptive rather than prescriptive analysis of behavior.
- PhotosynthesisRecall cards on how photoautotrophs capture light energy and build sugars: the overview and chemical equation, leaf and chloroplast structure, the light-dependent reactions (pigments, photosystems, water-splitting, chemiosmosis), and the Calvin cycle.
- Monopoly (Economics)Recall cards on monopoly: a single firm that is the only seller of a product with no close substitutes. How monopolies form and persist behind barriers to entry, natural monopolies from large economies of scale, legal monopolies and deregulation, control of a scarce resource, and the intellectual-property barriers of patents, trademarks, copyrights, and trade secrets, plus predatory pricing. Then how a profit-maximizing monopoly chooses output and price on its downward-sloping market demand curve: why marginal revenue is less than price and its curve lies below demand, finding output where marginal revenue equals marginal cost, reading price off the demand curve, and why the result is a lower quantity and a higher price than perfect competition.
- Consumer Choices (Economics)Recall cards on how consumers choose. The utility framework: total utility and marginal utility, marginal utility per dollar, and the utility-maximizing rule that sets the marginal utility per dollar equal across all goods (MU1/P1 = MU2/P2). How the budget constraint shifts when income changes and rotates when a price changes, and how a price change splits into a substitution effect and an income effect that together trace out the demand curve. Finally, behavioral economics: loss aversion and the Kahneman and Tversky finding, self-control problems, mental accounting, and how default enrollment shapes retirement saving.
- Positive Externalities and Public Goods (Economics)Recall cards on positive externalities, innovation, and public goods. Why the private sector underinvests in innovation: technology's positive spillovers, private versus social benefits, the private versus social rate of return, and how easy copying and captured benefits lead to underinvestment in research and development. How governments encourage innovation: intellectual property rights, direct R&D spending, R&D tax credits, and cooperative research. Public goods: nonexcludability and nonrivalry, private goods, national defense, the free rider problem, why markets underprovide public goods, and how taxes and alternative funding address it.
- MetabolismRecall cards on bioenergetics, thermodynamics, ATP, and enzymes.
- Meiosis and Sexual ReproductionRecall cards on meiosis and sexual reproduction: haploid and diploid cells, the two meiotic divisions (meiosis I and II), synapsis, crossing over and chiasmata, independent assortment, how meiosis differs from mitosis, why sexual reproduction persists, and the diploid-dominant, haploid-dominant, and alternation-of-generations life cycles.
- Cell Membranes and TransportRecall cards on the structure and function of plasma membranes and membrane transport.