Biology
103 ideas, each explained on one page with a 60-second lesson you can play right there.
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Allostatic load
Allostatic load is the cumulative physical wear and tear on your body caused by chronic or repeated stress.
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AMP-activated protein kinase
AMP-activated protein kinase (AMPK) is an enzyme inside cells that acts as a low-energy sensor.
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Amygdala
The amygdala is a pair of almond-sized clusters of neurons located deep inside the temporal lobes of the brain.
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Amyloid beta
Amyloid beta is a small protein fragment naturally produced and released by brain cells every day.
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Angiogenesis
Angiogenesis is the growth of new blood vessels from pre-existing ones.
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Animal echolocation Animal echolocation uses sound emission and returning echoes to measure object distance, size, and velocity in air and water.
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Antibody
An antibody is a specialized protein produced by immune cells to identify and latch onto foreign invaders like viruses and bacteria.
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Antibody-dependent cellular cytotoxicity
Antibody-dependent cellular cytotoxicity uses antibodies to guide immune cells like natural killer cells to destroy infected or cancerous cells.
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Antigen
An antigen is any molecule that can latch onto a specific immune receptor or antibody, acting like a chemical identifier.
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Apoptosis
Apoptosis is programmed cell death, a built-in biological routine where an unneeded or damaged cell systematically destroys itself.
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Assay
An assay is a laboratory test that detects or measures a specific target substance, called an analyte, in a sample.
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Autophagy
Autophagy is the cell's waste recycling system.
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Basal ganglia
The basal ganglia are a group of interconnected structures deep beneath the cerebral cortex.
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Benjamin Libet
Benjamin Libet was an American neuroscientist who studied human consciousness at the University of California, San Francisco.
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Bioluminescence
Bioluminescence is the production of light by a living organism through a chemical reaction.
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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.
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Calorie restriction
Calorie restriction lowers energy intake while maintaining essential nutrients, shifting cellular resources toward repair and metabolic health.
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Capsaicin
Capsaicin is the chemical compound that gives chili peppers their heat by triggering heat receptors in mammals while leaving birds unaffected.
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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.
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Carcinization
Carcinization is an evolutionary process where crustaceans that are not true crabs independently evolve crab-like bodies.
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Cell Culture
Cell culture is the process of growing living cells outside their natural organism inside controlled laboratory vessels.
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Checkpoint inhibitor
Cancer drugs called checkpoint inhibitors block off-switches on T cells, freeing the immune system to attack tumors.
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Chemotherapy
Chemotherapy is a systemic cancer treatment that uses drugs to disrupt cell division and trigger cell death.
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Chili Peppers
Chili peppers are the berry fruits of plants in the genus Capsicum, part of the nightshade family.
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Chronotype
A chronotype is a person's natural biological tendency to sleep and be active at specific times during a 24-hour day.
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Circadian Rhythm
Circadian rhythms are roughly 24-hour internal biological cycles.
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Complement System
The complement system is a network of about 50 blood proteins that automatically attack foreign invaders and clear damaged cells.
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Compound eye
A compound eye is a visual organ made of thousands of tiny independent light-sensing units called ommatidia.
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Convergent Evolution
Convergent evolution is the independent development of similar traits in species from completely different evolutionary branches.
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Creatine
Creatine is an organic compound that your body uses to rapidly recycle ATP, the molecule cells consume for energy.
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CRISPR
CRISPR is a microbial defense mechanism that stores virus DNA fragments and guides Cas enzymes to cut matching genetic sequences.
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Cytotoxicity
Cytotoxicity is the ability of a substance to damage or kill living cells.
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DNA Sequencing
DNA sequencing determines the precise order of bases in genetic material, shrinking full-genome reads from thirteen years to under a day.
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Dopamine
Dopamine is a chemical messenger that nerve cells use to communicate with one another.
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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.
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Electroreception
Electroreception is the biological ability to detect electrical fields in the surrounding environment.
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Enteric nervous system
The enteric nervous system is a mesh of 500 million neurons lining your digestive tract that runs your digestion.
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Enteroendocrine cell
Enteroendocrine cells are hormone-producing cells scattered throughout the lining of the stomach, intestines, and pancreas.
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Evolution of the eye
How simple light-sensing cells evolved into complex eyes multiple times across animal history through gradual natural selection.
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Fermentation
Fermentation is a chemical process where cells break down sugars to make energy without using oxygen.
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Fight-or-flight response
How the fight-or-flight response instantly redirects blood, releases glucose, and suppresses digestion during perceived threats.
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Frisson
Frisson is a brief physical reaction to rewarding stimuli like music or art that creates skin tingling, goosebumps, and pleasure.
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Gene Therapy
Gene therapy is a medical technique that treats disease by directly altering the genetic material inside a patient's living cells.
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Gut Microbiome
The gut microbiome contains 10 to 100 trillion microbes that ferment fiber, make vitamins, and influence mood via the gut-brain axis.
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Habanero
Learn what the habanero pepper is, how capsaicin defends its seeds, where it originated, and how its heat works on the Scoville scale.
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Human echolocation
Human echolocation is the ability to detect and map objects by producing sounds and listening to the returning echoes.
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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.
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Immune Memory
How specialized memory B and T cells recognize returning pathogens to eliminate them before they can cause illness.
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Immunology
Immunology is the branch of biology and medicine that studies how immune systems protect organisms from disease.
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Imprinting (psychology)
Imprinting is a rapid learning process during a brief early window that permanently shapes an animal's social and mating preferences.
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Insect Flight
Insects power flight by directly pulling wings or flexing their entire thorax, reaching wingbeat speeds that outpace their own nervous systems.
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Insomnia
Insomnia is a sleep disorder where a person struggles to fall asleep or stay asleep for as long as needed.
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Jalapeño A jalapeño is a medium-sized chili pepper cultivar of the species Capsicum annuum, typically measuring 5 to 10 centimeters long.
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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.
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Lactate dehydrogenase
Lactate dehydrogenase is an enzyme found in almost all living cells that converts pyruvate into lactate and back again.
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Major histocompatibility complex
Learn how the Major Histocompatibility Complex (MHC) presents protein fragments on cell surfaces to help T cells detect viruses and cancers.
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Melatonin
Melatonin is a hormone produced in the brain that tells the body when it is dark outside.
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Memory Consolidation
Memory consolidation is the brain process that stabilizes newly learned information so it can be stored as a long-term memory.
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Metastasis
Metastasis is the spread of cancer cells from a primary tumor to distant organs through the bloodstream or lymphatic system.
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mTOR
mTOR, or mechanistic target of rapamycin, is an enzyme inside your cells that acts as a master growth switch.
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Muscle Hypertrophy
Muscle hypertrophy is the enlargement of skeletal muscle caused by individual muscle cells growing thicker rather than multiplying.
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Muscle Soreness
Delayed onset muscle soreness comes from lengthening muscles under load, not lactic acid.
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Mutation
A mutation is a permanent change in the chemical sequence of an organism's DNA.
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Myenteric plexus
The myenteric plexus is a mesh-like network of nerve cells embedded between the muscle layers of your digestive tract.
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Myosatellite cell
A myosatellite cell is a dormant stem cell nestled against the outer edge of a skeletal muscle fiber.
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Natural killer cell
Natural killer cells are white blood cells that destroy tumor and virus-infected cells lacking normal MHC class I identity markers.
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Natural Selection
Natural selection is the process where organisms with traits better suited to their environment survive and reproduce more successfully.
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Necrosis
Necrosis is the premature, violent death of cells from trauma or infection.
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Oncogene
An oncogene is a mutated or overactive gene that has the potential to cause cancer.
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Oxytocin
Oxytocin is a peptide hormone, a small chemical messenger made of amino acids, produced in the brain's hypothalamus.
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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.
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Panspermia
Panspermia is the scientific hypothesis that microscopic life originated elsewhere and spreads across the universe inside rocks and comets.
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Piperine
Piperine is a plant compound known as an alkaloid that gives black and long pepper their pungent bite.
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Plasmid
A plasmid is a small loop of DNA that sits outside a cell's main chromosome and can copy itself independently.
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Polymerase Chain Reaction
Polymerase Chain Reaction (PCR) is a laboratory method that rapidly makes billions of copies of a specific piece of DNA.
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Prairie Vole
The prairie vole is a small, burrowing rodent native to the grasslands of North America.
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Prion
A prion is an infectious misfolded protein that forces healthy proteins of the same type to fold into its own abnormal shape.
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Progressive overload
Progressive overload is the training principle of gradually increasing the stress placed on your muscles and nervous system.
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Protein (nutrient)
Protein breaks down into amino acids to build tissue and enzymes.
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Protein folding
Proteins fold from simple amino acid chains into functional 3D shapes within milliseconds, driven by sequence, water, and chemical bonds.
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Proteostasis
Proteostasis is the cell's system for balancing the creation, folding, and destruction of all its proteins.
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Rapamycin Rapamycin is a bacterial compound that inhibits mTOR, halts cell division, stops transplant rejection, and is studied for extending lifespan.
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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.
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Recombinant DNA
Recombinant DNA combines genetic material from multiple sources into a single molecule, allowing host cells to produce new proteins.
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REM Sleep
REM sleep is a distinct phase of sleep where the brain acts nearly awake while the body's skeletal muscles are paralyzed.
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Sarcopenia
Sarcopenia is the progressive loss of skeletal muscle mass, strength, and function that happens with aging or prolonged immobility.
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Scoville Scale The Scoville scale is a measurement system that rates the heat of chili peppers in units called Scoville Heat Units (SHU).
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Serotonin
Serotonin is a chemical messenger that nerve cells use to communicate with each other and with the rest of the body.
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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.
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Sirtuin
Sirtuins are an ancient family of signaling proteins that act as master regulators of cellular metabolism and DNA repair.
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Skeletal muscle
Skeletal muscle is the striped tissue attached to your bones that contracts to move your skeleton and keep your body upright.
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Sleep debt
Sleep debt is the cumulative effect of not getting enough sleep over days or weeks.
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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.
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Stress Hormone
A stress hormone is a chemical signal released by endocrine glands to adjust your body during times of threat.
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T cell
Learn what T cells are, how they develop in the thymus, and how killer and helper T cells coordinate specific immune defenses.
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Tannins
Tannins are large, astringent biomolecules produced by plants that bind to proteins and force them out of solution.
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Tau protein
Tau protein stabilizes the internal skeleton of nerve cells, but clumps into neurofibrillary tangles during dementia and Alzheimer's disease.
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Terroir
Terroir describes how soil, slope, climate, and local microbes shape the distinct flavor of agricultural products like wine and cheese.
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TRPV1 Receptors
TRPV1 receptors are ion channels in sensory nerve cells that detect scalding heat, acids, and pungent chemicals like capsaicin.
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Tumor suppressor gene
A tumor suppressor gene is a stretch of DNA that produces proteins to control cell division and stop abnormal cell growth.
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Vagus nerve
The vagus nerve is the longest cranial nerve in your body, running from your brainstem down into your chest and abdomen.
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Viral vector
A viral vector is a modified virus stripped of its disease-causing parts and used to deliver genetic material into living cells.
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Wine fault
A wine fault is an unpleasant smell, taste, or appearance in a wine caused by chemical reactions or microbial spoilage.