Discover how the molecules of life interact, change, and keep cells working.
Biochemistry connects chemistry and biology by studying the molecules and reactions inside living things. It helps explain how cells obtain energy, build structures, copy genetic information, and control thousands of chemical reactions at once.
Amino-acid chains fold into shapes that perform many cellular jobs.
Learn MoreSugars and larger carbohydrates provide energy and structural materials.
Learn MoreFats and related molecules store energy and help form cell membranes.
Learn MoreDNA and RNA store, copy, and help use biological information.
Learn MoreBiological catalysts speed up reactions without being used up.
Learn MoreNetworks of reactions build molecules, release energy, and recycle materials.
Learn MoreProteins are made from smaller molecules called amino acids. Cells link amino acids into chains, and those chains fold into specific three-dimensional shapes. A protein's shape helps determine its function. Some proteins form structures, some carry materials, some send signals, and many act as enzymes that control chemical reactions.
Carbohydrates include simple sugars such as glucose and larger molecules built from many sugar units. Cells can break down glucose to release usable energy. Plants store carbohydrate energy in starch and build cell walls from cellulose, while animals store a carbohydrate called glycogen for shorter-term energy needs.
Lipids are a broad group of molecules that includes fats, oils, phospholipids, and steroids. Many lipids do not mix easily with water. Fats can store large amounts of chemical energy, while phospholipids naturally arrange into the double-layer structure that forms the basic framework of cell membranes.
DNA and RNA are nucleic acids built from units called nucleotides. DNA stores hereditary information, while several kinds of RNA help cells read and use that information. The order of nucleotides carries coded instructions that cells can use when producing proteins and regulating cell activities.
Enzymes are usually proteins that speed up chemical reactions by lowering the energy needed for those reactions to begin. Each enzyme works best with particular molecules and under certain conditions. Temperature, acidity, and the concentrations of reactants can all affect enzyme activity.
Metabolism is the complete set of chemical reactions happening in a living organism. Some pathways break large molecules into smaller ones and release energy, while others use energy to build proteins, nucleic acids, membranes, and other cell materials. Cells carefully regulate these linked pathways so that energy and raw materials are available when needed.