Biology

103 ideas, each explained on one page with a 60-second lesson you can play right there.

Allostatic load Allostatic load is the cumulative physical wear and tear on your body caused by chronic or repeated stress.
AMP-activated protein kinase AMP-activated protein kinase (AMPK) is an enzyme inside cells that acts as a low-energy sensor.
Amygdala The amygdala is a pair of almond-sized clusters of neurons located deep inside the temporal lobes of the brain.
Amyloid beta Amyloid beta is a small protein fragment naturally produced and released by brain cells every day.
Angiogenesis Angiogenesis is the growth of new blood vessels from pre-existing ones.
Animal echolocation Animal echolocation uses sound emission and returning echoes to measure object distance, size, and velocity in air and water.
Antibody An antibody is a specialized protein produced by immune cells to identify and latch onto foreign invaders like viruses and bacteria.
Antibody-dependent cellular cytotoxicity Antibody-dependent cellular cytotoxicity uses antibodies to guide immune cells like natural killer cells to destroy infected or cancerous cells.
Antigen An antigen is any molecule that can latch onto a specific immune receptor or antibody, acting like a chemical identifier.
Apoptosis Apoptosis is programmed cell death, a built-in biological routine where an unneeded or damaged cell systematically destroys itself.
Assay An assay is a laboratory test that detects or measures a specific target substance, called an analyte, in a sample.
Autophagy Autophagy is the cell's waste recycling system.
Basal ganglia The basal ganglia are a group of interconnected structures deep beneath the cerebral cortex.
Benjamin Libet Benjamin Libet was an American neuroscientist who studied human consciousness at the University of California, San Francisco.
Bioluminescence Bioluminescence is the production of light by a living organism through a chemical reaction.
Cabernet Sauvignon Cabernet Sauvignon is a hardy, thick-skinned red wine grape created by a chance seventeenth-century crossing of Cabernet franc and Sauvignon blanc.
Calorie restriction Calorie restriction lowers energy intake while maintaining essential nutrients, shifting cellular resources toward repair and metabolic health.
Capsaicin Capsaicin is the chemical compound that gives chili peppers their heat by triggering heat receptors in mammals while leaving birds unaffected.
CAR T cell A CAR T cell is a patient's own white blood cell that has been genetically modified in a laboratory to hunt and destroy cancer cells.
Carcinization Carcinization is an evolutionary process where crustaceans that are not true crabs independently evolve crab-like bodies.
Cell Culture Cell culture is the process of growing living cells outside their natural organism inside controlled laboratory vessels.
Checkpoint inhibitor Cancer drugs called checkpoint inhibitors block off-switches on T cells, freeing the immune system to attack tumors.
Chemotherapy Chemotherapy is a systemic cancer treatment that uses drugs to disrupt cell division and trigger cell death.
Chili Peppers Chili peppers are the berry fruits of plants in the genus Capsicum, part of the nightshade family.
Chronotype A chronotype is a person's natural biological tendency to sleep and be active at specific times during a 24-hour day.
Circadian Rhythm Circadian rhythms are roughly 24-hour internal biological cycles.
Complement System The complement system is a network of about 50 blood proteins that automatically attack foreign invaders and clear damaged cells.
Compound eye A compound eye is a visual organ made of thousands of tiny independent light-sensing units called ommatidia.
Convergent Evolution Convergent evolution is the independent development of similar traits in species from completely different evolutionary branches.
Creatine Creatine is an organic compound that your body uses to rapidly recycle ATP, the molecule cells consume for energy.
CRISPR CRISPR is a microbial defense mechanism that stores virus DNA fragments and guides Cas enzymes to cut matching genetic sequences.
Cytotoxicity Cytotoxicity is the ability of a substance to damage or kill living cells.
DNA Sequencing DNA sequencing determines the precise order of bases in genetic material, shrinking full-genome reads from thirteen years to under a day.
Dopamine Dopamine is a chemical messenger that nerve cells use to communicate with one another.
Dose–response relationship A dose–response relationship is the pattern showing how a living system reacts to different amounts of a substance or stressor over time.
Electroreception Electroreception is the biological ability to detect electrical fields in the surrounding environment.
Enteric nervous system The enteric nervous system is a mesh of 500 million neurons lining your digestive tract that runs your digestion.
Enteroendocrine cell Enteroendocrine cells are hormone-producing cells scattered throughout the lining of the stomach, intestines, and pancreas.
Evolution of the eye How simple light-sensing cells evolved into complex eyes multiple times across animal history through gradual natural selection.
Fermentation Fermentation is a chemical process where cells break down sugars to make energy without using oxygen.
Fight-or-flight response How the fight-or-flight response instantly redirects blood, releases glucose, and suppresses digestion during perceived threats.
Frisson Frisson is a brief physical reaction to rewarding stimuli like music or art that creates skin tingling, goosebumps, and pleasure.
Gene Therapy Gene therapy is a medical technique that treats disease by directly altering the genetic material inside a patient's living cells.
Gut Microbiome The gut microbiome contains 10 to 100 trillion microbes that ferment fiber, make vitamins, and influence mood via the gut-brain axis.
Habanero Learn what the habanero pepper is, how capsaicin defends its seeds, where it originated, and how its heat works on the Scoville scale.
Human echolocation Human echolocation is the ability to detect and map objects by producing sounds and listening to the returning echoes.
IC50 IC50 measures how much of a drug is needed to inhibit a biological target by 50 percent, acting as a core metric for inhibitor potency.
Immune Memory How specialized memory B and T cells recognize returning pathogens to eliminate them before they can cause illness.
Immunology Immunology is the branch of biology and medicine that studies how immune systems protect organisms from disease.
Imprinting (psychology) Imprinting is a rapid learning process during a brief early window that permanently shapes an animal's social and mating preferences.
Insect Flight Insects power flight by directly pulling wings or flexing their entire thorax, reaching wingbeat speeds that outpace their own nervous systems.
Insomnia Insomnia is a sleep disorder where a person struggles to fall asleep or stay asleep for as long as needed.
Jalapeño A jalapeño is a medium-sized chili pepper cultivar of the species Capsicum annuum, typically measuring 5 to 10 centimeters long.
Killer T Cells Killer T cells are white blood cells that hunt and destroy infected or cancerous cells by recognizing antigens displayed on MHC molecules.
Lactate dehydrogenase Lactate dehydrogenase is an enzyme found in almost all living cells that converts pyruvate into lactate and back again.
Major histocompatibility complex Learn how the Major Histocompatibility Complex (MHC) presents protein fragments on cell surfaces to help T cells detect viruses and cancers.
Melatonin Melatonin is a hormone produced in the brain that tells the body when it is dark outside.
Memory Consolidation Memory consolidation is the brain process that stabilizes newly learned information so it can be stored as a long-term memory.
Metastasis Metastasis is the spread of cancer cells from a primary tumor to distant organs through the bloodstream or lymphatic system.
mTOR mTOR, or mechanistic target of rapamycin, is an enzyme inside your cells that acts as a master growth switch.
Muscle Hypertrophy Muscle hypertrophy is the enlargement of skeletal muscle caused by individual muscle cells growing thicker rather than multiplying.
Muscle Soreness Delayed onset muscle soreness comes from lengthening muscles under load, not lactic acid.
Mutation A mutation is a permanent change in the chemical sequence of an organism's DNA.
Myenteric plexus The myenteric plexus is a mesh-like network of nerve cells embedded between the muscle layers of your digestive tract.
Myosatellite cell A myosatellite cell is a dormant stem cell nestled against the outer edge of a skeletal muscle fiber.
Natural killer cell Natural killer cells are white blood cells that destroy tumor and virus-infected cells lacking normal MHC class I identity markers.
Natural Selection Natural selection is the process where organisms with traits better suited to their environment survive and reproduce more successfully.
Necrosis Necrosis is the premature, violent death of cells from trauma or infection.
Oncogene An oncogene is a mutated or overactive gene that has the potential to cause cancer.
Oxytocin Oxytocin is a peptide hormone, a small chemical messenger made of amino acids, produced in the brain's hypothalamus.
P53 P53 is a protein that acts as a quality control inspector inside your cells, binding to DNA to control which genes get turned on.
Panspermia Panspermia is the scientific hypothesis that microscopic life originated elsewhere and spreads across the universe inside rocks and comets.
Piperine Piperine is a plant compound known as an alkaloid that gives black and long pepper their pungent bite.
Plasmid A plasmid is a small loop of DNA that sits outside a cell's main chromosome and can copy itself independently.
Polymerase Chain Reaction Polymerase Chain Reaction (PCR) is a laboratory method that rapidly makes billions of copies of a specific piece of DNA.
Prairie Vole The prairie vole is a small, burrowing rodent native to the grasslands of North America.
Prion A prion is an infectious misfolded protein that forces healthy proteins of the same type to fold into its own abnormal shape.
Progressive overload Progressive overload is the training principle of gradually increasing the stress placed on your muscles and nervous system.
Protein (nutrient) Protein breaks down into amino acids to build tissue and enzymes.
Protein folding Proteins fold from simple amino acid chains into functional 3D shapes within milliseconds, driven by sequence, water, and chemical bonds.
Proteostasis Proteostasis is the cell's system for balancing the creation, folding, and destruction of all its proteins.
Rapamycin Rapamycin is a bacterial compound that inhibits mTOR, halts cell division, stops transplant rejection, and is studied for extending lifespan.
Rare Earth hypothesis The Rare Earth hypothesis argues that simple life may be common, but complex, multicellular life requires an extremely rare set of circumstances.
Recombinant DNA Recombinant DNA combines genetic material from multiple sources into a single molecule, allowing host cells to produce new proteins.
REM Sleep REM sleep is a distinct phase of sleep where the brain acts nearly awake while the body's skeletal muscles are paralyzed.
Sarcopenia Sarcopenia is the progressive loss of skeletal muscle mass, strength, and function that happens with aging or prolonged immobility.
Scoville Scale The Scoville scale is a measurement system that rates the heat of chili peppers in units called Scoville Heat Units (SHU).
Serotonin Serotonin is a chemical messenger that nerve cells use to communicate with each other and with the rest of the body.
Single-chain variable fragment A single-chain variable fragment is an engineered fusion protein that links the binding tips of an antibody into a compact sensor.
Sirtuin Sirtuins are an ancient family of signaling proteins that act as master regulators of cellular metabolism and DNA repair.
Skeletal muscle Skeletal muscle is the striped tissue attached to your bones that contracts to move your skeleton and keep your body upright.
Sleep debt Sleep debt is the cumulative effect of not getting enough sleep over days or weeks.
Slow-Wave Sleep Slow-wave sleep is the deepest stage of non-REM sleep, defined by large delta waves that help the brain consolidate declarative memories.
Stress Hormone A stress hormone is a chemical signal released by endocrine glands to adjust your body during times of threat.
T cell Learn what T cells are, how they develop in the thymus, and how killer and helper T cells coordinate specific immune defenses.
Tannins Tannins are large, astringent biomolecules produced by plants that bind to proteins and force them out of solution.
Tau protein Tau protein stabilizes the internal skeleton of nerve cells, but clumps into neurofibrillary tangles during dementia and Alzheimer's disease.
Terroir Terroir describes how soil, slope, climate, and local microbes shape the distinct flavor of agricultural products like wine and cheese.
TRPV1 Receptors TRPV1 receptors are ion channels in sensory nerve cells that detect scalding heat, acids, and pungent chemicals like capsaicin.
Tumor suppressor gene A tumor suppressor gene is a stretch of DNA that produces proteins to control cell division and stop abnormal cell growth.
Vagus nerve The vagus nerve is the longest cranial nerve in your body, running from your brainstem down into your chest and abdomen.
Viral vector A viral vector is a modified virus stripped of its disease-causing parts and used to deliver genetic material into living cells.
Wine fault A wine fault is an unpleasant smell, taste, or appearance in a wine caused by chemical reactions or microbial spoilage.