answer string | choices dict | id string | kind string | lang string | question string | steps list | subject string | text string | topic string |
|---|---|---|---|---|---|---|---|---|---|
(C) Left ventricle; its thick wall pumps oxygenated blood through the aorta to the whole body. | {
"A": "Right atrium",
"B": "Right ventricle",
"C": "Left ventricle",
"D": "Left atrium"
} | bio_0401 | multiple_choice | en | Which heart chamber pumps blood to the body? | [
"Eliminate lung-side chambers.",
"Eliminate receiving atria.",
"Choose left ventricle."
] | biology | Answer: (C) The left ventricle powers body flow.
Steps:
1. Eliminate lung-side chambers.
2. Eliminate receiving atria.
3. Choose left ventricle.
Answer: (C) | physiology |
(A) Sucrose; table sugar joins glucose and fructose, unlike single sugars and long polymers. | {
"A": "Sucrose",
"B": "Glucose",
"C": "Starch",
"D": "Cellulose"
} | bio_0402 | multiple_choice | en | Which carbohydrate is a disaccharide? | [
"Eliminate single sugars.",
"Eliminate long polymers.",
"Choose sucrose."
] | biology | Answer: (A) Sucrose pairs two sugars.
Steps:
1. Eliminate single sugars.
2. Eliminate long polymers.
3. Choose sucrose.
Answer: (A) | biochemistry |
(D) Onion epidermis; plant cells build cellulose walls that animal cells lack. | {
"A": "Human cheek",
"B": "Red blood cell",
"C": "Neuron",
"D": "Onion epidermis"
} | bio_0403 | multiple_choice | en | Which cells have a cell wall? | [
"Eliminate animal cells.",
"Recall plant cellulose walls.",
"Choose onion epidermis."
] | biology | Answer: (D) Onion cells wall themselves.
Steps:
1. Eliminate animal cells.
2. Recall plant cellulose walls.
3. Choose onion epidermis.
Answer: (D) | cell_biology |
(B) AB; group AB red cells carry both A and B antigens. | {
"A": "O",
"B": "AB",
"C": "A",
"D": "B"
} | bio_0404 | multiple_choice | en | Which blood group carries both A and B antigens? | [
"Eliminate antigen-free group O.",
"Eliminate single-antigen groups.",
"Choose AB."
] | biology | Answer: (B) Group AB carries both antigens.
Steps:
1. Eliminate antigen-free group O.
2. Eliminate single-antigen groups.
3. Choose AB.
Answer: (B) | genetics |
(D) Mutace; pouze změny v sekvenci DNA vytvářejí nové alely. | {
"A": "Genetický drift",
"B": "Přírodní výběr",
"C": "Genový tok",
"D": "Mutace"
} | bio_0405 | multiple_choice | cs | Který proces vytváří zcela nové alely? | [
"Vylučte přeskupování starých alel.",
"Přiřaďte novinky změnám DNA.",
"Zvolte mutaci."
] | biology | Answer: (D) Nové alely tvoří mutace.
Steps:
1. Vylučte přeskupování starých alel.
2. Přiřaďte novinky změnám DNA.
3. Zvolte mutaci.
Answer: (D) | evolution |
(A) Rabbit; it feeds on plants, unlike the meat-eating predators listed. | {
"A": "Rabbit",
"B": "Fox",
"C": "Hawk",
"D": "Spider"
} | bio_0406 | multiple_choice | en | Which animal is a herbivore? | [
"Eliminate carnivores.",
"Identify the plant eater.",
"Choose rabbit."
] | biology | Answer: (A) Rabbits eat plants.
Steps:
1. Eliminate carnivores.
2. Identify the plant eater.
3. Choose rabbit.
Answer: (A) | ecology |
Minute ventilation is 62.5 liters per minute; sprinting lungs move ten times the resting volume. | null | bio_0407 | worked_example | en | A runner breathes 25 times per minute with tidal volume 2500 mL. Calculate minute ventilation. | [
"Multiply 2500 x 25 = 62500 mL per min.",
"Convert to 62.5 L per min.",
"Recompute: 62.5 x 1000 / 25 = 2500 mL."
] | biology | Answer: 62.5 L per min.
Steps:
1. Multiply 2500 x 25 = 62500 mL per min.
2. Convert to 62.5 L per min.
3. Recompute: 62.5 x 1000 / 25 = 2500 mL. | physiology |
About 0.056 moles; 10 grams divided by 180 grams per mole gives the amount. | null | bio_0408 | worked_example | en | Glucose has molar mass 180 g per mole. How many moles are in 10 g of glucose? | [
"Divide 10 / 180 = 0.0556.",
"Recompute: 0.0556 x 180 = 10.0.",
"Report about 0.056 mol."
] | biology | Answer: About 0.056 mol.
Steps:
1. Divide 10 / 180 = 0.0556.
2. Recompute: 0.0556 x 180 = 10.0.
3. Report about 0.056 mol. | biochemistry |
3200 cells after 2 hours; four doublings multiply the 200 founders sixteen-fold. | null | bio_0409 | worked_example | en | Bacteria double every 30 minutes. Starting from 200 cells, how many are present after 2 hours? | [
"Convert 2 hours = 120 minutes.",
"Count doublings: 120/30 = 4.",
"Compute 200 x 2^4 = 200 x 16 = 3200.",
"Recompute: 3200/200 = 16 = 2^4."
] | biology | Answer: 3200 cells.
Steps:
1. Convert 2 hours = 120 minutes.
2. Count doublings: 120/30 = 4.
3. Compute 200 x 2^4 = 200 x 16 = 3200.
4. Recompute: 3200/200 = 16 = 2^4. | cell_biology |
Podíl genotypu aaB_ je 3/16, tedy 18,75 procenta; pravděpodobnosti pro oba geny se násobí. | null | bio_0410 | worked_example | cs | Při křížení AaBb x AaBb s nezávislou segregací vypočítejte očekávaný podíl potomků s genotypem aaB_ (tedy aaBB nebo aaBb). | [
"Určete P(aa) = 1/4 a P(B_) = 3/4.",
"Vynásobte 1/4 x 3/4 = 3/16.",
"Převeďte na 0,1875, tedy 18,75 procenta.",
"Přepočítejte: 3/16 x 16 = 3 ze 16."
] | biology | Answer: 3/16, tedy 18,75 procenta.
Steps:
1. Určete P(aa) = 1/4 a P(B_) = 3/4.
2. Vynásobte 1/4 x 3/4 = 3/16.
3. Převeďte na 0,1875, tedy 18,75 procenta.
4. Přepočítejte: 3/16 x 16 = 3 ze 16. | genetics |
q equals 0.8, p equals 0.2, and carriers equal 32 percent; the common recessive phenotype gives a high q. | null | bio_0411 | worked_example | en | In a beetle population, 64 percent show a recessive trait. Assuming Hardy-Weinberg equilibrium, calculate q, p, and the carrier frequency. | [
"q = sqrt(0.64) = 0.8.",
"p = 1 - 0.8 = 0.2.",
"2pq = 2 x 0.2 x 0.8 = 0.32.",
"Recompute: 0.04+0.64+0.32=1.0."
] | biology | Answer: q=0.8, p=0.2, carriers=32%.
Steps:
1. q = sqrt(0.64) = 0.8.
2. p = 1 - 0.8 = 0.2.
3. 2pq = 2 x 0.2 x 0.8 = 0.32.
4. Recompute: 0.04+0.64+0.32=1.0. | evolution |
Shared resources collapse when each user profits by taking more while sharing the loss, as competing fleets overfish seas into ruin; quotas and reserves restore restraint. | null | bio_0412 | concept | en | Explain the tragedy of the commons with a fishing example. | [
"Share one resource openly.",
"Reward each for overuse.",
"Collapse stocks without rules."
] | biology | Answer: Open access tempts all to overtake.
Steps:
1. Share one resource openly.
2. Reward each for overuse.
3. Collapse stocks without rules. | ecology |
Sleep cycles through light, deep, and REM stages that consolidate memories, clear brain waste, and restore hormones; chronic loss impairs learning, immunity, and mood. | null | bio_0413 | concept | en | Explain sleep stages and why sleep matters. | [
"Cycle light, deep, and REM.",
"Consolidate memory and clear waste.",
"Restore hormones and mood."
] | biology | Answer: Sleep cleans and files the brain nightly.
Steps:
1. Cycle light, deep, and REM.
2. Consolidate memory and clear waste.
3. Restore hormones and mood. | physiology |
Starch links glucose in digestible coils for plant storage, glycogen branches it for fast animal release, and cellulose chains it into indigestible fibers that build plant walls. | null | bio_0414 | concept | en | Contrast starch, glycogen, and cellulose. | [
"Store glucose as starch.",
"Mobilize it as glycogen.",
"Build with cellulose fibers."
] | biology | Answer: Same glucose, three linkages, three jobs.
Steps:
1. Store glucose as starch.
2. Mobilize it as glycogen.
3. Build with cellulose fibers. | biochemistry |
Peroxizom odbourává mastné kyseliny a jedovaté peroxidy pomocí katalázy; v játrech pomáhá odbourávat i alkohol. | null | bio_0415 | concept | cs | Popište peroxizom a jeho funkci v buňce. | [
"Popište váček s oxidativními enzymy.",
"Vysvětlete odbourávání tuků a peroxidů.",
"Uveďte detoxikaci v játrech."
] | biology | Answer: Peroxizom spaluje tuky a ničí peroxidy.
Steps:
1. Popište váček s oxidativními enzymy.
2. Vysvětlete odbourávání tuků a peroxidů.
3. Uveďte detoxikaci v játrech. | cell_biology |
Clones share DNA yet differ because environments shape development, epigenetic marks diverge, and new mutations accumulate, so even identical twins carry small differences. | null | bio_0416 | concept | en | Explain why clones are not 100 percent identical. | [
"Share DNA but not surroundings.",
"Diverge by epigenetic marks.",
"Add fresh mutations."
] | biology | Answer: Same genes still meet different lives.
Steps:
1. Share DNA but not surroundings.
2. Diverge by epigenetic marks.
3. Add fresh mutations. | genetics |
Eyes evolved stepwise from light-sensitive patches to cups that sense direction, pinholes that form images, and lenses that focus them, each stage aiding survival. | null | bio_0417 | concept | en | Explain the stepwise evolution of eyes. | [
"Sense light with patches.",
"Aim with cups and pinholes.",
"Focus with lenses."
] | biology | Answer: Eyes grew from spots to cameras in steps.
Steps:
1. Sense light with patches.
2. Aim with cups and pinholes.
3. Focus with lenses. | evolution |
Renewables such as sunlight, wind, and timber regrow within human lifetimes, while nonrenewables such as coal and oil formed over eons and run out once burned. | null | bio_0418 | concept | en | Distinguish renewable from nonrenewable resources with examples. | [
"Define regrowth within lifetimes.",
"Name sun, wind, and timber.",
"Contrast coal and oil depletion."
] | biology | Answer: Renewables regrow; fossils only burn down.
Steps:
1. Define regrowth within lifetimes.
2. Name sun, wind, and timber.
3. Contrast coal and oil depletion. | ecology |
Fractures first bleed into a hematoma, then fibroblasts and osteoblasts bridge the gap with a soft and hard callus that remodels into strong lamellar bone over months. | null | bio_0419 | concept | en | Describe how broken bones heal. | [
"Clot into a hematoma.",
"Bridge with soft then hard callus.",
"Remodel into strong bone."
] | biology | Answer: Clots bridge into callus, then true bone.
Steps:
1. Clot into a hematoma.
2. Bridge with soft then hard callus.
3. Remodel into strong bone. | physiology |
Chlorofyl a a b zachycují červené a modré světlo pro fotosyntézu, karotenoidy chrání před přebytkem a na podzim zbarvují listí po rozpadu chlorofylu. | null | bio_0420 | concept | cs | Vysvětlete fotosyntetické pigmenty a jejich úlohu. | [
"Popište chlorofyly a záchyt světla.",
"Uveďte ochranné karotenoidy.",
"Vysvětlete podzimní barvy."
] | biology | Answer: Pigmenty chytají světlo a chrání před ním.
Steps:
1. Popište chlorofyly a záchyt světla.
2. Uveďte ochranné karotenoidy.
3. Vysvětlete podzimní barvy. | biochemistry |
(B) Egg cell; the human ovum is the largest human cell by volume, visible to the naked eye. | {
"A": "Skin cell",
"B": "Egg cell",
"C": "White blood cell",
"D": "Sperm cell"
} | bio_0421 | multiple_choice | en | Which is the largest human cell by volume? | [
"Eliminate tiny blood and sperm cells.",
"Recall the visible ovum.",
"Choose egg cell."
] | biology | Answer: (B) The ovum dwarfs other cells.
Steps:
1. Eliminate tiny blood and sperm cells.
2. Recall the visible ovum.
3. Choose egg cell.
Answer: (B) | cell_biology |
(D) 23; gametes carry one set of chromosomes, half the diploid number of 46. | {
"A": "46",
"B": "92",
"C": "2",
"D": "23"
} | bio_0422 | multiple_choice | en | How many chromosomes does a human gamete carry? | [
"Halve the diploid number.",
"Compute 46/2 = 23.",
"Choose 23."
] | biology | Answer: (D) Gametes carry 23 chromosomes.
Steps:
1. Halve the diploid number.
2. Compute 46/2 = 23.
3. Choose 23.
Answer: (D) | genetics |
(A) Single-celled prokaryotes; bacteria-like cells appear in the oldest fossils, billions of years before plants or animals. | {
"A": "Single-celled prokaryotes",
"B": "Fish",
"C": "Land plants",
"D": "Insects"
} | bio_0423 | multiple_choice | en | Which were the first living things on Earth? | [
"Eliminate complex multicellular groups.",
"Recall ancient bacterial fossils.",
"Choose single-celled prokaryotes."
] | biology | Answer: (A) Microbes came first.
Steps:
1. Eliminate complex multicellular groups.
2. Recall ancient bacterial fossils.
3. Choose single-celled prokaryotes.
Answer: (A) | evolution |
(C) Sunlight; light is a nonliving physical factor, unlike the organisms listed. | {
"A": "Trees",
"B": "Mushrooms",
"C": "Sunlight",
"D": "Deer"
} | bio_0424 | multiple_choice | en | Which is an abiotic factor in an ecosystem? | [
"Eliminate living organisms.",
"Identify the physical factor.",
"Choose sunlight."
] | biology | Answer: (C) Sunlight is abiotic.
Steps:
1. Eliminate living organisms.
2. Identify the physical factor.
3. Choose sunlight.
Answer: (C) | ecology |
(A) Játra; žluč tvoří jaterní buňky, žlučník ji jen skladuje a zahušťuje. | {
"A": "Játra",
"B": "Žlučník",
"C": "Slinivka břišní",
"D": "Slezina"
} | bio_0425 | multiple_choice | cs | Který orgán vytváří žluč? | [
"Vylučte pouhé skladování.",
"Přiřaďte tvorbu játrům.",
"Zvolte játra."
] | biology | Answer: (A) Žluč tvoří játra.
Steps:
1. Vylučte pouhé skladování.
2. Přiřaďte tvorbu játrům.
3. Zvolte játra.
Answer: (A) | physiology |
(D) Peptide; condensation between amino and carboxyl groups links amino acids into chains. | {
"A": "Hydrogen",
"B": "Ionic",
"C": "Glycosidic",
"D": "Peptide"
} | bio_0426 | multiple_choice | en | Which bond joins amino acids in a protein? | [
"Eliminate weak attractions.",
"Eliminate sugar linkages.",
"Choose peptide."
] | biology | Answer: (D) Peptide bonds chain amino acids.
Steps:
1. Eliminate weak attractions.
2. Eliminate sugar linkages.
3. Choose peptide.
Answer: (D) | biochemistry |
400 cells after 1 hour; four doublings multiply the 25 founders sixteen-fold. | null | bio_0427 | worked_example | en | Cells divide every 15 minutes. Starting from 25 cells, how many are present after 1 hour? | [
"Convert 1 hour = 60 minutes.",
"Count doublings: 60/15 = 4.",
"Compute 25 x 2^4 = 25 x 16 = 400.",
"Recompute: 400/25 = 16 = 2^4."
] | biology | Answer: 400 cells.
Steps:
1. Convert 1 hour = 60 minutes.
2. Count doublings: 60/15 = 4.
3. Compute 25 x 2^4 = 25 x 16 = 400.
4. Recompute: 400/25 = 16 = 2^4. | cell_biology |
Half of the sons, 50 percent, will have hemophilia; each son inherits his single X from his mother, who passes the mutant copy half the time. | null | bio_0428 | worked_example | en | A carrier woman (X^H X^h) has children with a normal man (X^H Y). What fraction of their sons will have hemophilia? | [
"List son genotypes: X^H Y or X^h Y.",
"Note mother passes X^h with probability 1/2.",
"Conclude 1/2 = 50 percent affected.",
"Recompute: half of all X copies from mother carry h."
] | biology | Answer: 1/2, i.e. 50 percent of sons.
Steps:
1. List son genotypes: X^H Y or X^h Y.
2. Note mother passes X^h with probability 1/2.
3. Conclude 1/2 = 50 percent affected.
4. Recompute: half of all X copies from mother carry h. | genetics |
Carriers are 42 percent; 2pq with p=0.7 and q=0.3 gives 0.42. | null | bio_0429 | worked_example | en | Allele frequencies are p=0.7 and q=0.3 in Hardy-Weinberg equilibrium. Calculate the frequency of heterozygous carriers. | [
"Compute 2pq = 2 x 0.7 x 0.3.",
"Evaluate 2 x 0.21 = 0.42.",
"Convert to 42 percent.",
"Recompute: 0.49+0.09+0.42=1.0."
] | biology | Answer: 42 percent carriers.
Steps:
1. Compute 2pq = 2 x 0.7 x 0.3.
2. Evaluate 2 x 0.21 = 0.42.
3. Convert to 42 percent.
4. Recompute: 0.49+0.09+0.42=1.0. | evolution |
Celkem 200 tun; výnos na hektar krát plocha dá celkovou sklizeň. | null | bio_0430 | worked_example | cs | Pole má 50 hektarů a výnos pšenice je 4 tuny na hektar. Vypočítejte celkovou sklizeň. | [
"Vynásobte 50 x 4 = 200.",
"Přiřaďte jednotku tuny.",
"Přepočítejte: 200 / 50 = 4."
] | biology | Answer: 200 tun.
Steps:
1. Vynásobte 50 x 4 = 200.
2. Přiřaďte jednotku tuny.
3. Přepočítejte: 200 / 50 = 4. | ecology |
About 71 beats per minute; 5000 mL per minute divided by 70 mL per beat gives the rate. | null | bio_0431 | worked_example | en | A heart pumps 5 liters per minute with a stroke volume of 70 mL. Calculate the heart rate. | [
"Convert 5 L = 5000 mL.",
"Divide 5000 / 70 = 71.4.",
"Report about 71 beats per min.",
"Recompute: 71.4 x 70 = 5000."
] | biology | Answer: About 71 beats per min.
Steps:
1. Convert 5 L = 5000 mL.
2. Divide 5000 / 70 = 71.4.
3. Report about 71 beats per min.
4. Recompute: 71.4 x 70 = 5000. | physiology |
Soap molecules carry a water-loving head and a grease-loving tail, so they surround oil droplets and lift them into water as micelles that rinse away. | null | bio_0432 | concept | en | Explain how soap cleans at the molecular level. | [
"Point tails into grease.",
"Point heads into water.",
"Rinse micelles away."
] | biology | Answer: Soap bridges grease and water.
Steps:
1. Point tails into grease.
2. Point heads into water.
3. Rinse micelles away. | biochemistry |
Cilia are short, numerous hairs that beat in waves to move fluids past cells, while flagella are long, few whips that propel cells themselves, as in sperm. | null | bio_0433 | concept | en | Distinguish cilia from flagella. | [
"Describe short many cilia.",
"Describe long few flagella.",
"Assign fluid moving versus swimming."
] | biology | Answer: Cilia sweep; flagella swim.
Steps:
1. Describe short many cilia.
2. Describe long few flagella.
3. Assign fluid moving versus swimming. | cell_biology |
Newborn heel-prick tests detect treatable disorders like PKU before symptoms appear, so a special diet begun in days prevents brain damage that ignorance would cause. | null | bio_0434 | concept | en | Explain how newborn genetic screening helps, with the PKU example. | [
"Test blood before symptoms.",
"Detect missing enzyme early.",
"Prevent harm with diet."
] | biology | Answer: Early tests let diets beat bad genes.
Steps:
1. Test blood before symptoms.
2. Detect missing enzyme early.
3. Prevent harm with diet. | genetics |
Pohlavní rozmnožování míchá geny rekombinací a oplozením, takže potomci jsou různorodí a populace se rychleji přizpůsobuje parazitům a změnám prostředí. | null | bio_0435 | concept | cs | Vysvětlete evoluční význam pohlavního rozmnožování. | [
"Popište míchání genů.",
"Zdůrazněte různorodost potomků.",
"Vysvětlete rychlejší přizpůsobení."
] | biology | Answer: Sex míchá geny proti parazitům a změnám.
Steps:
1. Popište míchání genů.
2. Zdůrazněte různorodost potomků.
3. Vysvětlete rychlejší přizpůsobení. | evolution |
Fragment edges face more wind, light, predators, and human disturbance than interiors, so small patches lose sensitive species that need deep, stable habitat. | null | bio_0436 | concept | en | Explain edge effects in fragmented habitats. | [
"Expose edges to wind and light.",
"Invite predators and invaders.",
"Lose interior specialists."
] | biology | Answer: Edges leak disturbance into fragments.
Steps:
1. Expose edges to wind and light.
2. Invite predators and invaders.
3. Lose interior specialists. | ecology |
Rising glucose triggers insulin, which stores sugar as glycogen, while falling glucose triggers glucagon, which releases it; the loop holds blood sugar steady. | null | bio_0437 | concept | en | Explain how insulin and glucagon regulate blood sugar. | [
"Store sugar with insulin.",
"Release sugar with glucagon.",
"Balance the loop."
] | biology | Answer: Insulin stores, glucagon releases.
Steps:
1. Store sugar with insulin.
2. Release sugar with glucagon.
3. Balance the loop. | physiology |
Heat and acids break the weak bonds holding protein shapes, so egg white turns opaque and firm as unfolded chains tangle; most denaturation is irreversible. | null | bio_0438 | concept | en | Explain protein denaturation with the cooked egg example. | [
"Break weak shape-holding bonds.",
"Unfold and tangle chains.",
"Note irreversible opacity."
] | biology | Answer: Cooking unfolds proteins for good.
Steps:
1. Break weak shape-holding bonds.
2. Unfold and tangle chains.
3. Note irreversible opacity. | biochemistry |
Vacuoles fill with water by osmosis and press the membrane against the wall, stiffening leaves and stems; wilting follows when water loss relaxes this pressure. | null | bio_0439 | concept | en | Explain how plant cells maintain turgor pressure. | [
"Fill vacuoles by osmosis.",
"Press membranes to walls.",
"Wilt when pressure drops."
] | biology | Answer: Water pressure stiffens plant cells.
Steps:
1. Fill vacuoles by osmosis.
2. Press membranes to walls.
3. Wilt when pressure drops. | cell_biology |
Genotyp je soubor alel, například Aa, zatímco fenotyp je pozorovatelný projev, například hnědé oči; stejný fenotyp mohou mít různé genotypy. | null | bio_0440 | concept | cs | Vysvětlete rozdíl mezi genotypem a fenotypem. | [
"Definujte genotyp jako alely.",
"Definujte fenotyp jako projev.",
"Ukažte překryv na příkladu."
] | biology | Answer: Genotyp jsou geny, fenotyp jejich projev.
Steps:
1. Definujte genotyp jako alely.
2. Definujte fenotyp jako projev.
3. Ukažte překryv na příkladu. | genetics |
(A) Chimpanzee; humans share a more recent ancestor with chimps and bonobos than with gorillas or orangutans. | {
"A": "Chimpanzee",
"B": "Gorilla",
"C": "Orangutan",
"D": "Gibbon"
} | bio_0441 | multiple_choice | en | Which is the closest living relative of humans? | [
"Eliminate distant apes.",
"Recall the recent split.",
"Choose chimpanzee."
] | biology | Answer: (A) Chimps are our closest kin.
Steps:
1. Eliminate distant apes.
2. Recall the recent split.
3. Choose chimpanzee.
Answer: (A) | evolution |
(C) Tropical rainforest; warm wet forests hold more species per area than any other biome. | {
"A": "Desert",
"B": "Tundra",
"C": "Tropical rainforest",
"D": "Taiga"
} | bio_0442 | multiple_choice | en | Which biome holds the most biodiversity? | [
"Eliminate harsh dry biomes.",
"Eliminate cold poor biomes.",
"Choose tropical rainforest."
] | biology | Answer: (C) Rainforests teem most.
Steps:
1. Eliminate harsh dry biomes.
2. Eliminate cold poor biomes.
3. Choose tropical rainforest.
Answer: (C) | ecology |
(D) Fallopian tube; sperm meet the egg in the oviduct, and the zygote then travels to the uterus. | {
"A": "Uterus",
"B": "Ovary",
"C": "Vagina",
"D": "Fallopian tube"
} | bio_0443 | multiple_choice | en | Where does fertilization usually occur in humans? | [
"Eliminate implantation site.",
"Eliminate gamete sources.",
"Choose fallopian tube."
] | biology | Answer: (D) Eggs meet sperm in the tube.
Steps:
1. Eliminate implantation site.
2. Eliminate gamete sources.
3. Choose fallopian tube.
Answer: (D) | physiology |
(B) Vitamin D; sunlight converts a skin precursor into this bone-protecting vitamin. | {
"A": "Vitamin C",
"B": "Vitamin D",
"C": "Vitamin B12",
"D": "Vitamin K"
} | bio_0444 | multiple_choice | en | Which vitamin is made in skin exposed to sunlight? | [
"Eliminate dietary-only vitamins.",
"Recall sun-driven synthesis.",
"Choose vitamin D."
] | biology | Answer: (B) Sunlight brews vitamin D.
Steps:
1. Eliminate dietary-only vitamins.
2. Recall sun-driven synthesis.
3. Choose vitamin D.
Answer: (B) | biochemistry |
(C) Mitochondrie; v nich probíhá buněčné dýchání uvolňující energii z glukózy. | {
"A": "Ribozom",
"B": "Jádro",
"C": "Mitochondrie",
"D": "Vakuola"
} | bio_0445 | multiple_choice | cs | Která organela uvolňuje energii z glukózy? | [
"Vylučte syntézu a skladování.",
"Přiřaďte dýchání mitochondriím.",
"Zvolte mitochondrie."
] | biology | Answer: (C) Energii uvolňují mitochondrie.
Steps:
1. Vylučte syntézu a skladování.
2. Přiřaďte dýchání mitochondriím.
3. Zvolte mitochondrie.
Answer: (C) | cell_biology |
(A) aa; two identical recessive alleles make the homozygous recessive genotype. | {
"A": "aa",
"B": "Aa",
"C": "AA",
"D": "A_"
} | bio_0446 | multiple_choice | en | Which genotype is homozygous recessive? | [
"Eliminate mixed alleles.",
"Eliminate dominant pairs.",
"Choose aa."
] | biology | Answer: (A) Homozygous recessive is aa.
Steps:
1. Eliminate mixed alleles.
2. Eliminate dominant pairs.
3. Choose aa.
Answer: (A) | genetics |
The allele frequency rises by 0.03 per generation on average; a 0.3 gain over 10 generations gives the rate. | null | bio_0447 | worked_example | en | Allele A rises in frequency from 0.2 to 0.5 over 10 generations. Calculate the average change per generation. | [
"Subtract 0.5 - 0.2 = 0.3.",
"Divide 0.3 / 10 = 0.03.",
"Recompute: 0.2 + 10 x 0.03 = 0.5."
] | biology | Answer: 0.03 per generation.
Steps:
1. Subtract 0.5 - 0.2 = 0.3.
2. Divide 0.3 / 10 = 0.03.
3. Recompute: 0.2 + 10 x 0.03 = 0.5. | evolution |
The estimated population is 200 fish; the Lincoln-Petersen formula scales the second catch by the marked fraction. | null | bio_0448 | worked_example | en | Researchers mark 40 fish, later catch 50 fish, and find 10 marked. Estimate the total population. | [
"Multiply 40 x 50 = 2000.",
"Divide 2000 / 10 = 200.",
"Recompute: 40/200 = 10/50 = 0.2."
] | biology | Answer: About 200 fish.
Steps:
1. Multiply 40 x 50 = 2000.
2. Divide 2000 / 10 = 200.
3. Recompute: 40/200 = 10/50 = 0.2. | ecology |
BMI is about 22.9; 70 kg divided by 1.75 squared meters gives a healthy-range value. | null | bio_0449 | worked_example | en | A person weighs 70 kg and is 1.75 m tall. Calculate the body mass index (BMI). | [
"Square height: 1.75^2 = 3.0625.",
"Divide 70 / 3.0625 = 22.86.",
"Report about 22.9.",
"Recompute: 22.86 x 3.0625 = 70.0."
] | biology | Answer: About 22.9.
Steps:
1. Square height: 1.75^2 = 3.0625.
2. Divide 70 / 3.0625 = 22.86.
3. Report about 22.9.
4. Recompute: 22.86 x 3.0625 = 70.0. | physiology |
36 gramů vody je 2 moly; hmotnost dělená molární hmotností 18 g/mol udává látkové množství. | null | bio_0450 | worked_example | cs | Molární hmotnost vody je 18 g/mol. Kolik molů je ve 36 g vody? | [
"Vydělte 36 / 18 = 2.",
"Přepočítejte: 2 x 18 = 36.",
"Uveďte 2 moly."
] | biology | Answer: 2 moly.
Steps:
1. Vydělte 36 / 18 = 2.
2. Přepočítejte: 2 x 18 = 36.
3. Uveďte 2 moly. | biochemistry |
The ratio is 2 to 1; surface 54 µm² over volume 27 µm³ shows why small cells exchange faster. | null | bio_0451 | worked_example | en | A cube-shaped cell has side 3 µm. Calculate its surface-area-to-volume ratio. | [
"Surface = 6 x 3^2 = 54 µm².",
"Volume = 3^3 = 27 µm³.",
"Ratio = 54/27 = 2:1.",
"Recompute: 2 x 27 = 54."
] | biology | Answer: SA:V = 2:1.
Steps:
1. Surface = 6 x 3^2 = 54 µm².
2. Volume = 3^3 = 27 µm³.
3. Ratio = 54/27 = 2:1.
4. Recompute: 2 x 27 = 54. | cell_biology |
Pleiotropy means one gene shapes many traits, as the sickle-cell allele alters red cells, blocks vessels, and resists malaria all at once. | null | bio_0452 | concept | en | Explain pleiotropy with the sickle-cell example. | [
"Define one gene, many effects.",
"Trace sickle allele damage.",
"Note malaria protection bonus."
] | biology | Answer: One gene can pull many strings.
Steps:
1. Define one gene, many effects.
2. Trace sickle allele damage.
3. Note malaria protection bonus. | genetics |
Distant lineages facing similar challenges evolve matching solutions, so birds, bats, and insects all fly on wings built from different starting parts. | null | bio_0453 | concept | en | Explain convergent evolution with the wing example. | [
"Pose the same challenge.",
"Build from different parts.",
"Land on matching wings."
] | biology | Answer: Same problems sculpt similar wings.
Steps:
1. Pose the same challenge.
2. Build from different parts.
3. Land on matching wings. | evolution |
Water evaporates from seas, condenses into clouds, falls as rain or snow, then flows and seeps back to the sea, driven endlessly by solar heat. | null | bio_0454 | concept | en | Describe the water cycle. | [
"Evaporate water with sun.",
"Condense into clouds.",
"Fall and flow back to seas."
] | biology | Answer: Seas feed clouds that rain them back.
Steps:
1. Evaporate water with sun.
2. Condense into clouds.
3. Fall and flow back to seas. | ecology |
Vzduch proudí průduškami do plicních sklípků, kde kyslík přechází do krve a oxid uhličitý ven; obrovský povrch sklípků výměnu zrychluje. | null | bio_0455 | concept | cs | Vysvětlete, jak plíce vyměňují plyny. | [
"Doveďte vzduch do sklípků.",
"Vyměňte kyslík za oxid uhličitý.",
"Využijte velký povrch."
] | biology | Answer: Sklípky mění vzduch za krevní plyny.
Steps:
1. Doveďte vzduch do sklípků.
2. Vyměňte kyslík za oxid uhličitý.
3. Využijte velký povrch. | physiology |
Lock-and-key pictures a rigid match between enzyme and substrate, while induced-fit lets the active site mold around the substrate for a tighter, catalytic grip. | null | bio_0456 | concept | en | Contrast the lock-and-key and induced-fit enzyme models. | [
"Fit rigid lock and key.",
"Mold induced-fit grip.",
"Prefer the flexible model."
] | biology | Answer: Enzymes grip more than they match.
Steps:
1. Fit rigid lock and key.
2. Mold induced-fit grip.
3. Prefer the flexible model. | biochemistry |
Mitochondria and chloroplasts descend from engulfed bacteria, shown by their own DNA, double membranes, and bacterium-sized ribosomes inside eukaryotic cells. | null | bio_0457 | concept | en | Explain the endosymbiotic theory of organelles. | [
"Engulf free bacteria.",
"Keep their DNA and membranes.",
"Inherit them ever since."
] | biology | Answer: Organelles are tamed bacteria.
Steps:
1. Engulf free bacteria.
2. Keep their DNA and membranes.
3. Inherit them ever since. | cell_biology |
Males carry only one X chromosome, so any recessive allele on it shows with no second copy to mask it, unlike females with two. | null | bio_0458 | concept | en | Explain why X-linked disorders affect males more often. | [
"Give males one X only.",
"Expose recessive alleles.",
"Mask them in females."
] | biology | Answer: One X leaves males uncovered.
Steps:
1. Give males one X only.
2. Expose recessive alleles.
3. Mask them in females. | genetics |
Five mass extinctions wiped out most species each, from ancient ice ages to the asteroid that ended the dinosaurs 66 million years ago and let mammals rise. | null | bio_0459 | concept | en | Explain mass extinctions with the dinosaur example. | [
"Count five great dyings.",
"Strike with asteroid winter.",
"Free mammals to rise."
] | biology | Answer: Catastrophes rebooted life five times.
Steps:
1. Count five great dyings.
2. Strike with asteroid winter.
3. Free mammals to rise. | evolution |
Potravní řetězec ukazuje přenos energie: trávu spase kobylka, tu uloví žába a tu had; každý článek část energie ztrácí. | null | bio_0460 | concept | cs | Vysvětlete potravní řetězec na příkladu louky. | [
"Začněte travou jako producentem.",
"Přidejte kobylku, žábu a hada.",
"Ukažte ztráty energie."
] | biology | Answer: Energie teče loukou vzhůru.
Steps:
1. Začněte travou jako producentem.
2. Přidejte kobylku, žábu a hada.
3. Ukažte ztráty energie. | ecology |
(B) Red blood cells; they are packed with hemoglobin that binds oxygen in the lungs and releases it in tissues. | {
"A": "White blood cells",
"B": "Red blood cells",
"C": "Platelets",
"D": "Bone cells"
} | bio_0461 | multiple_choice | en | Which blood cells carry oxygen? | [
"Eliminate immune defenders.",
"Eliminate clotting fragments.",
"Choose red blood cells."
] | biology | Answer: (B) Red cells ferry oxygen.
Steps:
1. Eliminate immune defenders.
2. Eliminate clotting fragments.
3. Choose red blood cells.
Answer: (B) | physiology |
(D) Fat; lipids yield about 9 kcal per gram, more than double the 4 kcal from carbohydrates or protein. | {
"A": "Sugar",
"B": "Protein",
"C": "Starch",
"D": "Fat"
} | bio_0462 | multiple_choice | en | Which nutrient provides the most energy per gram? | [
"Recall 4 kcal for carbs.",
"Recall 4 kcal for protein.",
"Choose fat at 9 kcal."
] | biology | Answer: (D) Fat packs most energy.
Steps:
1. Recall 4 kcal for carbs.
2. Recall 4 kcal for protein.
3. Choose fat at 9 kcal.
Answer: (D) | biochemistry |
(C) Cell membrane; its selective barrier decides which substances pass in and out of the cell. | {
"A": "Cell wall",
"B": "Nucleus",
"C": "Cell membrane",
"D": "Cytoplasm"
} | bio_0463 | multiple_choice | en | Which structure controls what enters and leaves the cell? | [
"Eliminate rigid support.",
"Eliminate inner contents.",
"Choose cell membrane."
] | biology | Answer: (C) The membrane guards the gates.
Steps:
1. Eliminate rigid support.
2. Eliminate inner contents.
3. Choose cell membrane.
Answer: (C) | cell_biology |
(A) Aa; every child gets A from one parent and a from the other, making all heterozygous. | {
"A": "Aa",
"B": "AA",
"C": "aa",
"D": "AA or aa"
} | bio_0464 | multiple_choice | en | A cross of AA x aa produces offspring that are all what genotype? | [
"Pair A with a.",
"Make every child Aa.",
"Choose Aa."
] | biology | Answer: (A) All offspring are Aa.
Steps:
1. Pair A with a.
2. Make every child Aa.
3. Choose Aa.
Answer: (A) | genetics |
(D) Fosilie; paleontologie zkoumá zkameněliny a z nich čte historii života. | {
"A": "Živé rostliny",
"B": "Počasí",
"C": "Buňky",
"D": "Fosilie"
} | bio_0465 | multiple_choice | cs | Co studuje paleontologie? | [
"Vylučte živé objekty.",
"Přiřaďte zkameněliny.",
"Zvolte fosilie."
] | biology | Answer: (D) Paleontologie čte fosilie.
Steps:
1. Vylučte živé objekty.
2. Přiřaďte zkameněliny.
3. Zvolte fosilie.
Answer: (D) | evolution |
(B) Oak tree; as a photosynthetic plant it produces its own food, unlike consumers and decomposers. | {
"A": "Wolf",
"B": "Oak tree",
"C": "Mushroom",
"D": "Hawk"
} | bio_0466 | multiple_choice | en | Which organism is a producer? | [
"Eliminate meat eaters.",
"Eliminate decomposers.",
"Choose oak tree."
] | biology | Answer: (B) Oaks make their own food.
Steps:
1. Eliminate meat eaters.
2. Eliminate decomposers.
3. Choose oak tree.
Answer: (B) | ecology |
Cardiac output reaches 15 liters per minute; 150 beats times 100 mL triples the resting flow. | null | bio_0467 | worked_example | en | During exercise the heart beats 150 times per minute with stroke volume 100 mL. Calculate cardiac output. | [
"Multiply 150 x 100 = 15000 mL per min.",
"Convert to 15 L per min.",
"Recompute: 15 x 1000 / 150 = 100 mL."
] | biology | Answer: 15 L per min.
Steps:
1. Multiply 150 x 100 = 15000 mL per min.
2. Convert to 15 L per min.
3. Recompute: 15 x 1000 / 150 = 100 mL. | physiology |
The snack provides 165 kcal; protein and carbs give 4 kcal per gram and fat gives 9. | null | bio_0468 | worked_example | en | A snack contains 10 g protein, 20 g carbohydrate, and 5 g fat. Calculate its energy in kcal (protein 4, carbohydrate 4, fat 9 kcal per gram). | [
"Protein: 10 x 4 = 40.",
"Carbs: 20 x 4 = 80.",
"Fat: 5 x 9 = 45.",
"Sum 40+80+45 = 165 kcal.",
"Recompute: 165-45-80 = 40 = 10 x 4."
] | biology | Answer: 165 kcal.
Steps:
1. Protein: 10 x 4 = 40.
2. Carbs: 20 x 4 = 80.
3. Fat: 5 x 9 = 45.
4. Sum 40+80+45 = 165 kcal.
5. Recompute: 165-45-80 = 40 = 10 x 4. | biochemistry |
The cell is 200 micrometers long; one tenth of the 2 mm field gives 0.2 mm. | null | bio_0469 | worked_example | en | A microscope field of view is 2 mm wide and a cell spans one tenth of it. Calculate the cell's length in micrometers. | [
"Divide 2 / 10 = 0.2 mm.",
"Convert 0.2 mm = 200 µm.",
"Recompute: 200 x 10 = 2000 µm = 2 mm."
] | biology | Answer: 200 µm.
Steps:
1. Divide 2 / 10 = 0.2 mm.
2. Convert 0.2 mm = 200 µm.
3. Recompute: 200 x 10 = 2000 µm = 2 mm. | cell_biology |
Pravděpodobnost heterozygota Aa je 1/2, tedy 50 procent; Punnettův čtverec dává dvě ze čtyř kombinací. | null | bio_0470 | worked_example | cs | Při křížení Aa x Aa vypočítejte pravděpodobnost, že potomek bude heterozygot Aa. | [
"Sestavte čtverec: AA, Aa, Aa, aa.",
"Spočítejte Aa: 2 ze 4.",
"Převeďte na 1/2 = 50 procent.",
"Přepočítejte: 1/4 + 1/2 + 1/4 = 1."
] | biology | Answer: 1/2, tedy 50 procent.
Steps:
1. Sestavte čtverec: AA, Aa, Aa, aa.
2. Spočítejte Aa: 2 ze 4.
3. Převeďte na 1/2 = 50 procent.
4. Přepočítejte: 1/4 + 1/2 + 1/4 = 1. | genetics |
q equals 0.3, p equals 0.7, and homozygous dominant AA are 49 percent; squaring p gives p². | null | bio_0471 | worked_example | en | Nine percent of a population show a recessive trait. Assuming Hardy-Weinberg equilibrium, calculate q, p, and the homozygous dominant frequency. | [
"q = sqrt(0.09) = 0.3.",
"p = 1 - 0.3 = 0.7.",
"p² = 0.7 x 0.7 = 0.49.",
"Recompute: 0.49+0.09+0.42=1.0."
] | biology | Answer: q=0.3, p=0.7, AA=49%.
Steps:
1. q = sqrt(0.09) = 0.3.
2. p = 1 - 0.3 = 0.7.
3. p² = 0.7 x 0.7 = 0.49.
4. Recompute: 0.49+0.09+0.42=1.0. | evolution |
Persistent toxins like mercury concentrate at each feeding step, so top predators carry doses thousands of times higher than the water around them. | null | bio_0472 | concept | en | Explain biomagnification of toxins up food chains. | [
"Absorb toxins from prey.",
"Concentrate them each step.",
"Poison top predators most."
] | biology | Answer: Toxins magnify toward the top.
Steps:
1. Absorb toxins from prey.
2. Concentrate them each step.
3. Poison top predators most. | ecology |
Vaccines present harmless antigens that trigger antibody production and memory cells, so a later real infection meets a primed, rapid immune response. | null | bio_0473 | concept | en | Explain how vaccines train immunity without causing disease. | [
"Present harmless antigens.",
"Build antibodies and memory.",
"Defeat real germs fast."
] | biology | Answer: Vaccines rehearse immunity safely.
Steps:
1. Present harmless antigens.
2. Build antibodies and memory.
3. Defeat real germs fast. | physiology |
Each enzyme's active site fits only matching substrates by shape and charge, so lactase digests lactose while ignoring other sugars entirely. | null | bio_0474 | concept | en | Explain why enzymes are specific to their substrates. | [
"Shape the active site.",
"Match shape and charge.",
"Reject wrong substrates."
] | biology | Answer: Active sites admit only fits.
Steps:
1. Shape the active site.
2. Match shape and charge.
3. Reject wrong substrates. | biochemistry |
Jádro uchovává DNA v chromozomech, řídí syntézu bílkovin a dělí se při mitóze; jaderné póry propouštějí RNA a bílkoviny. | null | bio_0475 | concept | cs | Popište buněčné jádro a jeho funkci. | [
"Uložte DNA do chromozomů.",
"Řiďte syntézu bílkovin.",
"Propouštějte látky póry."
] | biology | Answer: Jádro je řídicí knihovna buňky.
Steps:
1. Uložte DNA do chromozomů.
2. Řiďte syntézu bílkovin.
3. Propouštějte látky póry. | cell_biology |
Sequencing revealed only about 20,000 protein-coding genes with most DNA noncoding, showing complexity comes from gene regulation, not gene count. | null | bio_0476 | concept | en | State the main finding of the Human Genome Project. | [
"Count about 20,000 genes.",
"Note mostly noncoding DNA.",
"Credit regulation for complexity."
] | biology | Answer: Few genes, vast regulation.
Steps:
1. Count about 20,000 genes.
2. Note mostly noncoding DNA.
3. Credit regulation for complexity. | genetics |
Rare resistant mutants survive antibiotics while others die, then multiply freely; overuse of drugs speeds this selection toward untreatable superbugs. | null | bio_0477 | concept | en | Explain how antibiotic resistance evolves in bacteria. | [
"Mutate rare resistance.",
"Kill the susceptible.",
"Multiply survivors freely."
] | biology | Answer: Drugs select the mutants they spare.
Steps:
1. Mutate rare resistance.
2. Kill the susceptible.
3. Multiply survivors freely. | evolution |
Greenhouse gases trap outgoing heat and keep Earth habitable, but burning fossil fuels thickens the blanket and overheats the climate. | null | bio_0478 | concept | en | Explain the natural and enhanced greenhouse effect. | [
"Trap heat with gases.",
"Keep Earth habitable.",
"Overheat by added fuels."
] | biology | Answer: A thin blanket warms; a thick one cooks.
Steps:
1. Trap heat with gases.
2. Keep Earth habitable.
3. Overheat by added fuels. | ecology |
Nerve signals release calcium that lets myosin heads grip actin and pull filaments past each other, shortening sarcomeres until ATP resets the grip. | null | bio_0479 | concept | en | Explain muscle contraction by the sliding filament model. | [
"Release calcium on signal.",
"Pull actin with myosin.",
"Reset grips with ATP."
] | biology | Answer: Myosin rows pull actin inward.
Steps:
1. Release calcium on signal.
2. Pull actin with myosin.
3. Reset grips with ATP. | physiology |
Bílkoviny jsou řetězce aminokyselin spojených peptidovou vazbou; jejich tvar určuje funkci, od enzymů po svaly a protilátky. | null | bio_0480 | concept | cs | Vysvětlete, co jsou bílkoviny a z čeho se skládají. | [
"Popište řetězce aminokyselin.",
"Uveďte peptidovou vazbu.",
"Spojte tvar s funkcí."
] | biology | Answer: Bílkoviny jsou tvarované řetězce aminokyselin.
Steps:
1. Popište řetězce aminokyselin.
2. Uveďte peptidovou vazbu.
3. Spojte tvar s funkcí. | biochemistry |
(D) Chloroplast; chlorophyll pigments sit in thylakoid membranes where light reactions run. | {
"A": "Mitochondrion",
"B": "Nucleus",
"C": "Ribosome",
"D": "Chloroplast"
} | bio_0481 | multiple_choice | en | Where is chlorophyll found in a plant cell? | [
"Eliminate energy burners.",
"Eliminate builders and control.",
"Choose chloroplast."
] | biology | Answer: (D) Chlorophyll greens the chloroplasts.
Steps:
1. Eliminate energy burners.
2. Eliminate builders and control.
3. Choose chloroplast.
Answer: (D) | cell_biology |
(A) Adenine-thymine; A pairs with T and G pairs with C in the double helix. | {
"A": "Adenine-thymine",
"B": "Adenine-guanine",
"C": "Thymine-guanine",
"D": "Cytosine-thymine"
} | bio_0482 | multiple_choice | en | Which bases pair together in DNA? | [
"Pair A with T.",
"Pair G with C.",
"Choose adenine-thymine."
] | biology | Answer: (A) A meets T, G meets C.
Steps:
1. Pair A with T.
2. Pair G with C.
3. Choose adenine-thymine.
Answer: (A) | genetics |
(C) Darwin; he proposed natural selection as the mechanism of evolution in 1859. | {
"A": "Mendel",
"B": "Linnaeus",
"C": "Darwin",
"D": "Pasteur"
} | bio_0483 | multiple_choice | en | Which scientist proposed evolution by natural selection? | [
"Eliminate genetics founder.",
"Eliminate naming and germ pioneers.",
"Choose Darwin."
] | biology | Answer: (C) Darwin named selection.
Steps:
1. Eliminate genetics founder.
2. Eliminate naming and germ pioneers.
3. Choose Darwin.
Answer: (C) | evolution |
(B) Bacteria; decomposer microbes break dead matter into nutrients, unlike producers and consumers. | {
"A": "Grass",
"B": "Bacteria",
"C": "Rabbit",
"D": "Hawk"
} | bio_0484 | multiple_choice | en | Which organism is a decomposer? | [
"Eliminate producers.",
"Eliminate consumers.",
"Choose bacteria."
] | biology | Answer: (B) Bacteria recycle the dead.
Steps:
1. Eliminate producers.
2. Eliminate consumers.
3. Choose bacteria.
Answer: (B) | ecology |
(C) Sítnice; obsahuje čípky a tyčinky měnící světlo na nervové signály. | {
"A": "Čočka",
"B": "Duhovka",
"C": "Sítnice",
"D": "Sklivec"
} | bio_0485 | multiple_choice | cs | Která část oka vnímá světlo? | [
"Vylučte optiku a clonu.",
"Přiřaďte čidla sítnici.",
"Zvolte sítnici."
] | biology | Answer: (C) Světlo vnímá sítnice.
Steps:
1. Vylučte optiku a clonu.
2. Přiřaďte čidla sítnici.
3. Zvolte sítnici.
Answer: (C) | physiology |
(A) Insulin; this blood-sugar hormone is a protein, unlike the sugars and starch listed. | {
"A": "Insulin",
"B": "Glucose",
"C": "Sucrose",
"D": "Starch"
} | bio_0486 | multiple_choice | en | Which molecule is a protein? | [
"Eliminate simple sugars.",
"Eliminate sugar polymers.",
"Choose insulin."
] | biology | Answer: (A) Insulin is protein.
Steps:
1. Eliminate simple sugars.
2. Eliminate sugar polymers.
3. Choose insulin.
Answer: (A) | biochemistry |
160 cells are in interphase; the four mitotic phases sum to 20 percent, leaving 80 percent resting. | null | bio_0487 | worked_example | en | Of 200 cells, 10 percent are in prophase, 5 percent in metaphase, 3 percent in anaphase, and 2 percent in telophase. How many are in interphase? | [
"Sum mitotic: 10+5+3+2 = 20 percent.",
"Interphase = 100-20 = 80 percent.",
"Compute 200 x 0.8 = 160.",
"Recompute: 160/200 = 0.8."
] | biology | Answer: 160 cells in interphase.
Steps:
1. Sum mitotic: 10+5+3+2 = 20 percent.
2. Interphase = 100-20 = 80 percent.
3. Compute 200 x 0.8 = 160.
4. Recompute: 160/200 = 0.8. | cell_biology |
Half the offspring, 50 percent, will be tall; the Tt x tt cross gives Tt and tt in equal numbers. | null | bio_0488 | worked_example | en | In peas tall (T) is dominant to short (t). For the cross Tt x tt, calculate the probability of tall offspring. | [
"List offspring: Tt or tt.",
"Note equal 1/2 chances.",
"Conclude Tt = 1/2 = 50 percent tall.",
"Recompute: 1/2 + 1/2 = 1."
] | biology | Answer: 1/2, i.e. 50 percent tall.
Steps:
1. List offspring: Tt or tt.
2. Note equal 1/2 chances.
3. Conclude Tt = 1/2 = 50 percent tall.
4. Recompute: 1/2 + 1/2 = 1. | genetics |
The frequency rises by 0.016 per generation on average; a 0.8 gain over 50 generations gives the rate. | null | bio_0489 | worked_example | en | A dark-wing allele rises from frequency 0.1 to 0.9 over 50 generations. Calculate the average change per generation. | [
"Subtract 0.9 - 0.1 = 0.8.",
"Divide 0.8 / 50 = 0.016.",
"Recompute: 0.1 + 50 x 0.016 = 0.9."
] | biology | Answer: 0.016 per generation.
Steps:
1. Subtract 0.9 - 0.1 = 0.8.
2. Divide 0.8 / 50 = 0.016.
3. Recompute: 0.1 + 50 x 0.016 = 0.9. | evolution |
V lese roste asi 5000 stromů; hustota krát plocha dá celkový počet. | null | bio_0490 | worked_example | cs | Hustota lesa je 200 stromů na hektar a jeho plocha je 25 hektarů. Vypočítejte počet stromů. | [
"Vynásobte 200 x 25 = 5000.",
"Přepočítejte: 5000 / 25 = 200.",
"Uveďte asi 5000 stromů."
] | biology | Answer: Asi 5000 stromů.
Steps:
1. Vynásobte 200 x 25 = 5000.
2. Přepočítejte: 5000 / 25 = 200.
3. Uveďte asi 5000 stromů. | ecology |
Plasma volume is 2.75 liters; 55 percent of 5 liters remains after the 45 percent cell fraction. | null | bio_0491 | worked_example | en | Blood volume is 5 liters with hematocrit 45 percent. Calculate the plasma volume. | [
"Plasma fraction = 100-45 = 55 percent.",
"Compute 5 x 0.55 = 2.75 L.",
"Recompute: 2.75/5 = 0.55."
] | biology | Answer: 2.75 L of plasma.
Steps:
1. Plasma fraction = 100-45 = 55 percent.
2. Compute 5 x 0.55 = 2.75 L.
3. Recompute: 2.75/5 = 0.55. | physiology |
The pH scale runs 0 to 14 as a logarithmic ladder where each step means ten times more H+ ions, with 7 neutral, lower acidic, and higher basic. | null | bio_0492 | concept | en | Explain the pH scale and what its numbers mean. | [
"Run scale 0 to 14.",
"Multiply ions tenfold per step.",
"Split acid, neutral, base."
] | biology | Answer: pH counts acidity in tens.
Steps:
1. Run scale 0 to 14.
2. Multiply ions tenfold per step.
3. Split acid, neutral, base. | biochemistry |
Apoptosis is orderly self-destruction that carves fingers from webbed hands and removes damaged cells before they turn cancerous. | null | bio_0493 | concept | en | Explain apoptosis and why cells self-destruct. | [
"Define programmed death.",
"Sculpt hands from webs.",
"Delete damaged cells."
] | biology | Answer: Cells die neatly to build bodies.
Steps:
1. Define programmed death.
2. Sculpt hands from webs.
3. Delete damaged cells. | cell_biology |
Epigenetic marks switch genes on or off without changing DNA letters, so identical twins diverge as diet, stress, and age rewrite their marks. | null | bio_0494 | concept | en | Explain epigenetics and how identical twins diverge. | [
"Mark genes without rewriting.",
"Switch expression by life.",
"Diverge twin fates."
] | biology | Answer: Life annotates shared genomes.
Steps:
1. Mark genes without rewriting.
2. Switch expression by life.
3. Diverge twin fates. | genetics |
Speciace je vznik nových druhů: populace se oddělí bariérou, hromadí rozdíly a nakonec se spolu nemohou množit. | null | bio_0495 | concept | cs | Vysvětlete, co je to speciace. | [
"Oddělte populace bariérou.",
"Hromaďte genetické rozdíly.",
"Ztraťte schopnost křížení."
] | biology | Answer: Speciace dělí druhy bariérami.
Steps:
1. Oddělte populace bariérou.
2. Hromaďte genetické rozdíly.
3. Ztraťte schopnost křížení. | evolution |
Carbon cycles from air into plants by photosynthesis, through food chains and decay, and back to air by respiration and burning fossil fuels. | null | bio_0496 | concept | en | Describe the carbon cycle. | [
"Fix air carbon in plants.",
"Pass it through food and decay.",
"Return it by breath and burning."
] | biology | Answer: Life borrows air carbon in loops.
Steps:
1. Fix air carbon in plants.
2. Pass it through food and decay.
3. Return it by breath and burning. | ecology |
Sensory nerves carry a tap signal to the spinal cord, which orders the muscle to jerk at once, bypassing the slow brain for speed. | null | bio_0497 | concept | en | Explain the reflex arc with the knee-jerk example. | [
"Sense the tap.",
"Relay through the cord.",
"Jerk without brain delay."
] | biology | Answer: Reflexes shortcut the brain.
Steps:
1. Sense the tap.
2. Relay through the cord.
3. Jerk without brain delay. | physiology |
Saturated fats pack straight chains solid at room temperature, while kinked unsaturated chains stay liquid as oils and suit heart health better. | null | bio_0498 | concept | en | Contrast saturated and unsaturated fats. | [
"Pack straight chains solid.",
"Kink bent chains liquid.",
"Favor oils for hearts."
] | biology | Answer: Straight fats harden; kinked fats flow.
Steps:
1. Pack straight chains solid.
2. Kink bent chains liquid.
3. Favor oils for hearts. | biochemistry |
Stem cells divide into copies of themselves plus specialized cells, offering repair for blood, skin, and perhaps one day damaged hearts and nerves. | null | bio_0499 | concept | en | Explain stem cells and their medical promise. | [
"Copy self endlessly.",
"Birth specialized cells.",
"Repair blood and beyond."
] | biology | Answer: Stem cells renew and rebuild.
Steps:
1. Copy self endlessly.
2. Birth specialized cells.
3. Repair blood and beyond. | cell_biology |
Mutace je změna v DNA: bodová mění jedno písmeno, delece maže a inzerce přidává; většina je neutrálních, některé škodí a vzácné prospívají. | null | bio_0500 | concept | cs | Vysvětlete, co je mutace a jaké jsou její typy. | [
"Definujte změnu v DNA.",
"Rozlište záměnu, deleci a inzerci.",
"Zhodnoťte dopady."
] | biology | Answer: Mutace přepisují písmena DNA.
Steps:
1. Definujte změnu v DNA.
2. Rozlište záměnu, deleci a inzerci.
3. Zhodnoťte dopady. | genetics |
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