BiochemistryBiochemistry is the study of the chemical reactions and interactions that take place in living organisms, especially the structure and function of their components, such as proteins, carbohydrates, lipids, nucleic acids, and small molecules present in cells. Biochemistry could also (now) be defined as being the chemistry of enzyme-mediated reactions, whether in vivo or in the test tube, with natural or artificially modified enzymes and other chemicals. Development of biochemistry The dawn of biochemistry may have been the discovery of the first enzyme, diastase, in 1833 by Anselme Payen. In 1828, Friedrich Wšhler published a paper about the synthesis of urea, proving that organic compounds can be created artificially, in contrast to the common belief of the time that organic compounds can only be made by living organisms. Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, NMR, radioisotopic labelling, electron microscopy and molecular dynamics simulations. These techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle. Today, the findings of biochemistry are used in many areas, from genetics to molecular biology and from agriculture to medicine. The first application of biochemistry was probably the making of bread using yeast, about 5000 years ago. Categories Biochemistry is principally concerned with the chemistry of substances that can be classified into a few major categories: * Carbohydrates * Lipids * Proteins and Amino acids * Nucleic acids The bulk of biochemical investigation focuses on the properties of proteins, many of which are enzymes. For historical reasons, the biochemistry of metabolism has been one of the most extensively described aspect of the cell. Important modern-day areas include the genetic code (DNA, RNA), protein synthesis, cell membrane transport, signal transduction and energy decomposition cycles.