Bioquímica

Molècula d'Hemoglobina

La bioquímica és l'estudi de les reaccions químiques i interaccions que es donen en organismes vius, incloent l'estudi i l'estructura de proteïnes, carbohidrats, lípids, àcids nucleics i altres molècules presents en cèl·lules. En general, també es pot considerar part de la bioquímica l'estudi de qualsevol reacció química catalitzada per enzims naturals o artificials, tant si té lloc in vivo o in vitro.

Wöhler observes the synthesis of urea.

El terme bioquímica (prové del grec: βίος, bios, "vida" i egipci kēme, "earth") és l'estudi del chemical processos en organismes vius. It deals with the structure and function of cellular components, such as proteins, carbohidrats, lípids, àcids nucleics, i altres biomolèculas. Chemical biology aims to answer many questions arising from biochemistry by using eines developed within síntesi química.

Although there are a vast number of different biomolecules, many are complex and large molecules (called polimers) that are composed of similar repeating subunits (called monomers). Each class of polymeric biomolecule has a different set of subunit types. P.ex., a protein is a polymer made up of 20 or more aminoàcids. La bioquímica estudia les propietats químiques of important biological molecules, like proteins, in particular the chemistry of enzim-catalyzed reactions.

The biochemistry of cell metabolism and the sistema endocrí has been extensively described. Other areas of biochemistry include the codi genètic (ADN, ARN), sintesi proteica, membrana cel·lular transport, i transducció de senyal.

This article only discusses terrestrial biochemistry (carbon- and water-based), as all the life forms we know are on Earth. Since life forms alive today are hypothesized by most to have descended from the same common ancestor, they have similar biochemistries, even for matters that seem to be essentially arbitrary, such as handedness of various biomolecules. It is unknown whether alternative biochemistries are possible or practical.

History of biochemistry

Wöhler observes the synthesis of urea.

Friedrich Wöhler

Originally, it was generally believed that life was not subject to the laws of science the way non-life was. It was thought that only living beings could produce the molecules of life (from other, previously existing biomolecules). Then, in 1828, Friedrich Wöhler published a paper on the synthesis of urea, proving that organic compounds can be created artificially.

The dawn of biochemistry may have been the discovery of the first enzyme, diastase (today called amylase), in 1833 by Anselme Payen. Eduard Buchner contributed the first demonstration of a complex biochemical process outside of a cell in 1896: alcoholic fermentation in cell extracts of yeast. Although the term “biochemistry” seems to have been first used in 1882, it is generally accepted that the formal coinage of biochemistry occurred in 1903 by Carl Neuberg, a German chemist. Previously, this area would have been referred to as physiological chemistry. Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, NMR spectroscopy, radioisotopic labeling, 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 (citric acid cycle).

Today, the findings of biochemistry are used in many areas, from genetics to molecular biology and from agriculture to medicine.

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