Biochemistry

Biochemistry is the machinery level—the specific molecules and reactions that make everything else possible. Every term in this category describes a component or process at the chemical scale. It's where biology stops being metaphor and becomes mechanism. The core insight of biochemistry is that speed requires energy. There's no free acceleration. Every biological speedup—faster reactions, quicker responses, more throughput—requires ATP or some equivalent. The vocabulary here explains why organisms can't just 'try harder.' Effort has caloric cost, and budgets are finite. Biochemistry vocabulary helps you think about fundamental constraints. Enzymes are catalysts that enable specific reactions—like specialized employees who make certain work possible. ATP is the universal energy currency—like actual currency, it's required for everything and always in limited supply. These aren't loose analogies; they're the actual mechanisms that constrain all living systems. The terms here reveal why some things that seem simple are actually hard. Why can't you just speed up? Because faster reactions require more enzyme, which requires more energy, which requires more food, which requires more foraging, which might not be worth the speed gain. Every 'why not just...' question has a biochemical answer. After exploring this category, you'll understand that there are no free optimizations—every improvement costs something.

Adenine One of the four nucleotide bases in DNA and RNA, abbreviated as 'A'. Adenine pairs with thymine (in DNA) or uracil (in R... Aerobic Requiring or occurring in the presence of oxygen. Aerobic respiration is the most efficient way to extract energy from f... Albumin The most abundant protein in blood plasma, responsible for maintaining osmotic pressure and transporting various molecul... Amino Acid The building blocks of proteins. Twenty standard amino acids combine in various sequences to form all proteins in living... Amylase An enzyme that breaks down complex starches into simple sugars your body can actually use. The bridge between stored ene... Anabolism The set of metabolic pathways that construct molecules from smaller units, requiring energy input. The opposite of catab... Anaerobic Not requiring or occurring in the absence of oxygen. Anaerobic metabolism is less efficient but allows life in oxygen-fr... Antioxidant A molecule that prevents oxidation of other molecules by neutralizing free radicals. Antioxidants protect cells from oxi... ATP (Adenosine Triphosphate) The primary energy currency of cells. A molecule that stores and transfers energy for cellular processes, releasing ener... Catabolism The set of metabolic pathways that break down molecules into smaller units, releasing energy. The opposite of anabolism... Cellulose A complex carbohydrate that forms the primary structural component of plant cell walls. The most abundant organic compou... Chitin A tough, protective polysaccharide that forms the exoskeletons of insects and crustaceans and the cell walls of fungi. T... Cytosine One of the four nucleotide bases in DNA and RNA, abbreviated as 'C'. Cytosine pairs with guanine through three hydrogen... Denaturation The process by which proteins or nucleic acids lose their three-dimensional structure and thus their function, typically... Electrochemical Relating to chemical reactions that involve the transfer of electrons, creating electrical current, or using electrical... Enzyme A protein that catalyzes (speeds up) specific biochemical reactions without being consumed in the process. Enzymes make... Gluconeogenesis The metabolic pathway that synthesizes glucose from non-carbohydrate sources like amino acids, lactate, and glycerol. Ho... Glycolysis The metabolic pathway that breaks down glucose into pyruvate, producing a small amount of ATP quickly. Occurs in the cyt... Guanine One of the four nucleotide bases in DNA and RNA, abbreviated as 'G'. Guanine pairs with cytosine through three hydrogen... Hemoglobin The iron-containing protein in red blood cells that carries oxygen from lungs to tissues and carbon dioxide back. What m... Lignin A complex polymer that provides structural support in plant cell walls, particularly in wood. Lignin makes plants rigid... Melanin A pigment that gives color to skin, hair, and eyes. Melanin absorbs UV radiation, protecting cells from DNA damage cause... Metabolism The sum of all chemical reactions occurring within an organism to maintain life, including breaking down nutrients for e... Phospholipid A type of lipid molecule with a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails. The primary compo... Phosphorylation The addition of a phosphate group to a molecule, typically a protein. A key mechanism for activating or deactivating cel... Photosynthesis The process by which plants, algae, and some bacteria convert light energy, carbon dioxide, and water into glucose and o... Protein Large molecules made of amino acid chains that perform most cellular functions. Proteins include enzymes (catalysts), st... Respiration (Cellular) The metabolic process by which cells break down glucose and other organic molecules to release energy stored in their ch... Substrate The molecule(s) upon which an enzyme acts. The starting material that is transformed in an enzymatic reaction. Thymine One of the four nucleotide bases in DNA, abbreviated as 'T'. Thymine pairs with adenine through two hydrogen bonds. In R...