QUIZAlcohol Metabolism Explorer
How quickly a person breaks down alcohol depends on two enzymes, ADH1B and ALDH2, and on the DNA that codes for them. A single base change can alter one...
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QUIZ
LABAlien Evolution Lab
Species that share a recent common ancestor also share inherited traits, so biologists can reconstruct evolutionary history by comparing anatomy, DNA and...
LABAquarium Simulator
An aquatic ecosystem depends on a balance between producers, consumers and the nutrients cycling among them, so a change in one population ripples through...
GAMEATP Cycle Game
ATP is the cell's short term energy currency. Attaching a phosphate to ADP stores energy in a new bond, and breaking that bond by hydrolysis releases...
LABBed Bug Treatment Lab
When a pesticide kills most of a population, the few individuals carrying a resistance allele survive and pass it on, so that allele grows more common...
LABBlood Sugar Regulation App
Blood glucose has to stay within a narrow range, and the pancreas keeps it there by releasing insulin when sugar rises after a meal. When beta cells fail,...
SONGBond, Fold, Function
A song about how proteins get their shape, from amino acid side chains to quaternary structure.
LABCash Crop
Plants only grow as well as their conditions allow, and inside a sealed container every one of those conditions is a decision: light, water, nutrient...
SIMCell Builder
Cells are the smallest units of life, and the organelles inside them each carry out a specific job that keeps the cell working. Different cell types build...
LABCell Cycle Simulator
Cells grow and divide through the cell cycle, a repeating sequence of growth, DNA replication and mitosis that builds tissues and replaces worn out cells....
QUIZCell Differentiation Simulator
Every cell in a body carries the same DNA, yet a nerve cell and a muscle cell are nothing alike, because each switches on a different set of genes. What...
LABCell Diffusion Explorer
Cells stay alive by controlling what crosses the membrane. Some molecules drift down a concentration gradient at no energy cost, while others must be...
SIMCell Signaling Interactive
Cells must communicate to coordinate their activities, respond to their environment, and build complex multicellular organisms. This communication happens...
QUIZCellular Energy and Thermodynamics
Living things run on a constant flow of energy. Cells break down fuel molecules to release it, then spend ATP to pay for the reactions that build and...
QUIZCFTR Channel Simulation
Cystic fibrosis starts with a tiny change in one gene. Deleting three nucleotides from CFTR removes a single amino acid, so the chloride channel misfolds,...
QUIZChi-Square Statistical Activity
Real biological data never match a prediction exactly, so biologists need a way to judge whether a difference is meaningful or just chance. The chi-square...
GAMEContractile
Freshwater cells constantly take in water because their surroundings are more dilute than their cytoplasm, and without a way to push it back out they...
QUIZDAPA (Data Analysis Practice App)
Biology runs on evidence, and evidence arrives as messy data that has to be organized, graphed and interpreted before it means anything. Working with real...
SIMDNA Replication Simulator
Before a cell divides it must copy its entire genome, and a team of enzymes does the work: unwinding the helix, separating the strands, laying down...
SIMElectron Transport Chain Simulator
The final stage of cellular respiration passes electrons from NADH and FADH2 down a chain of proteins in the inner mitochondrial membrane. The energy...
LABELISA Virtual Laboratory
An ELISA uses the precise fit between an antibody and its antigen to detect tiny amounts of a substance in a sample, with a color change reporting the...
QUIZEndosymbiotic Theory Interactive
Mitochondria and chloroplasts were once free living bacteria that were swallowed by an ancestral cell and never left. That partnership is what allowed...
LABEnvironmental Effects on Phenotype Lab
A genotype does not fix a phenotype on its own. Identical genes can produce very different traits depending on the conditions an organism develops in. Two...
LABEnzyme Environment Explorer
An enzyme is a protein whose folded shape forms an active site that fits a particular substrate, so anything that changes the shape changes the reaction...
LABEnzyme Lock and Key Interactive
Enzymes are proteins that speed up the chemical reactions life depends on, and each one only acts on a substrate whose shape fits its active site. Because...
SIMEpic genetics Simulator
Every cell in an organism carries the same DNA, yet cells behave differently because they express different genes. Expression runs from DNA through...
GAMEEutrophication Tycoon
Fertilizer that does not stay in the soil washes into nearby water, where extra nitrogen and phosphorus feed algae blooms that strip the water of oxygen....
3DFluid Mosaic Model
A cell membrane is not a solid wall. It is a fluid sheet of phospholipids with proteins drifting through it like boats, an arrangement that lets the...
SIMFood Guesser
Every food carries its own mix of energy, protein, fat, carbohydrate and other nutrients, and that profile reflects what the food is made from. Reading...
LABForest Ecosystem Simulation
A forest is a community of populations whose numbers are held in check by the resources around them and by each other. Growth slows as a population...
LABFounder’s Effect Simulator
When a few individuals start a new population, they carry only a small sample of the original gene pool, so allele frequencies can shift by chance alone....
CALCGene Mapping Interactive
Genes that sit close together on the same chromosome tend to be inherited together, and crossing over during meiosis occasionally separates them. The...
SIMGlycogen Hydrolysis Lab
Animals store energy as glycogen, a branched polymer of glucose whose bonds form when water is removed and break when water is added back. Hydrolysis of...
QUIZGraphing & Statistics Tool
Biological measurements vary from one sample to the next, so scientists use statistics to judge whether a difference between two groups is real or just...
GAMEGTS (Gram Theft Strepto)
A bacterium in the body faces a constant problem: find nutrients, avoid immune cells hunting it down, and survive antibiotics. Those pressures explain...
LABIVF Simulator
In vitro fertilization brings egg and sperm together outside the body, then supports the resulting embryo through its first divisions. It works because...
SIMLight Reactions Simulator
The light dependent reactions capture energy from sunlight and store it in a chemical form the cell can use. Splitting water supplies electrons, which...
LABMembrane Explorer
A cell membrane lets some substances through and holds others back, which is how a cell keeps its internal conditions steady while still taking in what it...
QUIZMembrane Fatty Acid Explorer
A cell membrane has to stay fluid to work, but cold makes the fatty acid tails of its phospholipids pack together and stiffen. Organisms respond by...
GAMEMolecule Mania
Living things are built from four main classes of large molecule: proteins, nucleic acids, lipids and carbohydrates. Each has a structure suited to its...
SONGMonomer to Monomer
A song about dehydration synthesis and hydrolysis, the paired reactions that build and break polymers.
SIMNucleic Acid Builder
DNA and RNA are built from nucleotides, each made of a phosphate group, a five carbon sugar and a nitrogenous base, and the order of those bases carries...
LABOcean Acidification Simulator
As the ocean absorbs carbon dioxide from the atmosphere, the water grows more acidic and less carbonate is left dissolved in it. Corals, clams and other...
QUIZOperail: Gene Regulation Simulation
Bacteria do not transcribe every gene all the time; they switch genes on and off as conditions change. In an operon, a cluster of related genes shares one...
LABOsmosis Simulator
Water crosses a semipermeable membrane from where solutes are dilute toward where they are concentrated, so a cell swells or shrinks depending on the...
GAMEPedigree Profiteers
Traits such as speed and stamina are inherited, so breeders choose which animals reproduce in the hope of concentrating those traits in the next...
GAMEPhotosynthesis Electron Jumper
Photosynthesis begins when light strikes chlorophyll and lifts an electron to a higher energy level. That excited electron is passed along a chain of...
SIMPlant Response Simulator
Plants cannot move, so they respond to their surroundings by changing the way they grow. Hormones carried through the plant tissue make shoots bend toward...
QUIZPocket Mice Natural Selection
Natural selection acts when some individuals survive and reproduce better than others because of the traits they carry. In desert pocket mice, coat color...
QUIZPopulation Growth Calculator
Populations grow when births outpace deaths, but no population grows without limit forever. The exponential and logistic equations capture that story...
QUIZPowerhouse (Mitochondria Simulator)
Mitochondria finish the job of pulling energy out of food. The citric acid cycle strips electrons from fuel molecules, the electron transport chain uses...
3DProtein Builder
A protein begins as a chain of amino acids, but the order of those amino acids decides how the chain folds, and the folded shape decides what the protein...
QUIZProtein Modification Visualizer
Proteins made at the endoplasmic reticulum are rarely finished when they are built. They travel by vesicle to the Golgi apparatus, where added sugars,...
3DProtein Visualizer
A protein's shape decides what it can do, from copying DNA to letting a virus latch onto a host cell. Seen in three dimensions, the link between structure...
SIMReaction Diagram Sandbox
Metabolism is a web of linked reactions in which the product of one enzyme becomes the substrate of the next, and a few control points set how fast the...
QUIZRedOx Challenge
Photosynthesis and cellular respiration are, at heart, a long relay of electrons passed between molecules. At every step one molecule loses electrons and...
LABReproductive Isolation Simulator
A new species forms when two populations stop interbreeding and their gene pools drift apart. The barriers that separate them can act before mating, such...
QUIZSickle Cell Simulation
A single nucleotide change in the HBB gene alters one amino acid in hemoglobin, and that tiny change makes red blood cells bend into rigid sickles that...
SIMSignal Transduction Visualizer
Cells respond to hormones and other signals that cannot cross the membrane, so the message is caught by a receptor and relayed inward along a chain of...
QUIZSimpson Diversity Index Calculator
A community with many species spread evenly is more diverse than one that a single species dominates, and Simpson's Diversity Index captures both richness...
SONGSmooth Flow
A song about lipids, and how double bonds in fatty acids control whether a fat stays fluid.
QUIZSodium-Potassium Pump
Cells spend a large share of their energy on the sodium potassium pump, which uses ATP to push three sodium ions out for every two potassium ions it...
SONGSPONCH
A song about the six elements that make up living things and where each one shows up.
QUIZSugar Factory (Photosynthesis Simulator)
Photosynthesis turns light energy into sugar. The light-dependent reactions in the thylakoid membrane capture that energy as ATP and NADPH, which the...
SIMVariant Ventures
Viruses copy their genetic material imperfectly, so each round of replication can throw up variants with slightly different traits. Host immunity then...
LABVirtual Gel Electrophoresis
Gel electrophoresis separates DNA fragments and proteins by pulling them through a gel with an electric field, so smaller molecules travel further and...
LABVirtual PCR
PCR copies a chosen stretch of DNA millions of times, which is how a lab gets enough material to test for a pathogen, a mutation or a match. Success rests...
LABVirtual Restriction Digest
Restriction enzymes cut DNA wherever a specific short sequence appears, which lets biologists break a genome into predictable fragments and move genes...
QUIZVocab Studio
Biology carries a heavy technical vocabulary, and terms learned once fade quickly without review. This tool covers 299 AP Biology terms spanning all eight...
SONGWater in the Summertime
A summer-memory song that doubles as a walkthrough of water polarity, hydrogen bonding, and why biology depends on both.
LABWater Potential Calculator
Water moves into and out of plant cells by osmosis, always travelling from higher to lower water potential. Water potential combines solute potential,...
QUIZWater Properties Explorer
Water behaves strangely for such a small molecule, and life depends on it. Its polar structure lets water molecules hydrogen bond to one another, which...
LABYeast Respiration Lab
Cells release energy from sugar by respiration, but when oxygen runs short yeast switches to fermentation, producing ethanol and carbon dioxide instead....
SONGYou Are Like Carbohydrates
A song about carbohydrate structure, from single sugars to branched polysaccharides.
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