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Encyclopedia > Metabolism
Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism.
Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism.

Metabolism is the complete set of chemical reactions that occur in living cells. These processes are the basis of life, allowing cells to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories. Catabolism yields energy, an example being the breakdown of food in cellular respiration. Anabolism, on the other hand, uses this energy to construct components of cells such as proteins and nucleic acids. Image File history File links Download high resolution version (1534x1100, 453 KB) File links The following pages link to this file: Adenosine triphosphate User:Benjah-bmm27/Gallery ... Image File history File links Download high resolution version (1534x1100, 453 KB) File links The following pages link to this file: Adenosine triphosphate User:Benjah-bmm27/Gallery ... Coenzyme A Coenzymes are small organic non-protein molecules that carry chemical groups between enzymes. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... For other uses, see Chemical reaction (disambiguation). ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... For other uses, see Life (disambiguation). ... Anabolism is the aspect of metabolism that contributes to growth. ... Cellular respiration was discovered by mad scientist Mr. ... Anabolism is the metabolic process that builds larger molecules from smaller ones. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Look up nucleic acid in Wiktionary, the free dictionary. ...


The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed into another by a sequence of enzymes. Enzymes are crucial to metabolism because they allow cells to drive desirable but thermodynamically unfavorable reactions by coupling them to favorable ones. Enzymes also allow the regulation of metabolic pathways in response to changes in the cell's environment or signals from other cells. In biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... This article is about the study of energy transformation in Biology and related subjects. ... In physics, two systems are coupled if they are interacting with each other. ... Cell signaling is part of a complex system of communication that governs basic cellular activities and coordinates cell actions. ...


The metabolism of an organism determines which substances it will find nutritious and which it will find poisonous. For example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals.[1] The speed of metabolism, the metabolic rate, also influences how much food an organism will require. The updated USDA food pyramid, published in 2005, is a general nutrition guide for recommended food consumption for humans. ... The skull and crossbones symbol (Jolly Roger) traditionally used to label a poisonous substance. ... Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... Hydrogen sulfide (hydrogen sulphide in British English) is the chemical compound with the formula H2S. This colorless, toxic and flammable gas is responsible for the foul odor of rotten eggs and flatulence. ...


A striking feature of metabolism is the similarity of the basic metabolic pathways between even vastly different species. For example, the set of chemical intermediates in the citric acid cycle are found universally, among living cells as diverse as the unicellular bacteria Escherichia coli and huge multicellular organisms like elephants.[2] This shared metabolic structure is most likely the result of the high efficiency of these pathways, and of their early appearance in evolutionary history.[3][4] Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... A cluster of Escherichia coli bacteria magnified 10,000 times. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... E. coli redirects here. ... Wild-type Caenorhabditis elegans hermaphrodite stained to highlight the nuclei of all cells Multicellular organisms are organisms consisting of more than one cell, and having differentiated cells that perform specialized functions. ... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas antiquus † Elephas beyeri † Elephas celebensis † Elephas cypriotes † Elephas ekorensis † Elephas falconeri † Elephas iolensis † Elephas planifrons † Elephas platycephalus † Elephas recki † Stegodon † Mammuthus † Elephantidae (the elephants) is a family of pachyderm, and the only remaining family in the order Proboscidea...

Contents

Key biochemicals

Further information: Biomolecule, cell (biology) and biochemistry
Structure of a triacylglycerol lipid.
Structure of a triacylglycerol lipid.

Most of the structures that make up animals, plants and microbes are made from three basic classes of molecule: amino acids, carbohydrates and lipids (often called fats). As these molecules are vital for life, metabolism focuses on making these molecules, in the construction of cells and tissues, or breaking them down and using them as a source of energy, in the digestion and use of food. Many important biochemicals can be joined together to make polymers such as DNA and proteins. These macromolecules are essential parts of all living organisms. Some of the most common biological polymers are listed in the table below. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Biochemistry is the study of the chemical processes in living organisms. ... Image File history File links Download high-resolution version (1100x893, 274 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Fat Trimyristin User:Benjah-bmm27/Gallery User:Ben Mills/Gallery ... Image File history File links Download high-resolution version (1100x893, 274 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Fat Trimyristin User:Benjah-bmm27/Gallery User:Ben Mills/Gallery ... This article is about lipid molecules, for FAT see File Allocation Table. ... Phenylalanine is one of the standard amino acids. ... Lactose is a disaccharide found in milk. ... Some common lipids. ... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A macromolecule is a molecule composed of a very large number of atoms. ...

Type of molecule Name of monomer forms Name of polymer forms Examples of polymer forms
Amino acids Amino acids Proteins (also called polypeptides) Fibrous proteins and globular proteins
Carbohydrates Monosaccharides Polysaccharides Starch, glycogen and cellulose
Nucleic acids Nucleotides Polynucleotides DNA and RNA

In chemistry, a monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer. ... A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... Phenylalanine is one of the standard amino acids. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Fibrous proteins, also called scleroproteins, are long filamentous protein molecules that form one of the two main classes of tertiary structure protein (the other being globular proteins). ... 3-dimensional structure of hemoglobin, a globular protein. ... Lactose is a disaccharide found in milk. ... Monosaccharides are the simplest form of carbohydrates. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ... Starch (CAS# 9005-25-8, chemical formula (C6H10O5)n,[1]) is a mixture of amylose and amylopectin (usually in 20:80 or 30:70 ratios). ... This article does not cite any references or sources. ... Cellulose as polymer of β-D-glucose Cellulose in 3D Cellulose (C6H10O5)n is a polysaccharide of beta-glucose. ... Look up nucleic acid in Wiktionary, the free dictionary. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... Polynucleotide literally means many nucleotides. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Ribonucleic acid or RNA is a nucleic acid polymer consisting of nucleotide monomers that plays several important roles in the processes that translate genetic information from deoxyribonucleic acid (DNA) into protein products; RNA acts as a messenger between DNA and the protein synthesis complexes known as ribosomes, forms vital portions...

Amino acids and proteins

Proteins are made of amino acids arranged in a linear chain and joined together by peptide bonds. Many proteins are the enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as the proteins in the cytoskeleton that form a system of scaffolding to maintain cell shape.[5] Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes and the cell cycle.[6] A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Phenylalanine is one of the standard amino acids. ... A peptide bond is a chemical bond that is formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (H2O). ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... In chemistry and biology, catalysis is the acceleration (increase in rate) of a chemical reaction by means of a substance, called a catalyst, that is itself not consumed by the overall reaction. ... The eukaryotic cytoskeleton. ... This article is about the temporary framework. ... Cell signaling is part of a complex system of communication that governs basic cellular activities and coordinates cell actions. ... Each antibody binds to a specific antigen; an interaction similar to a lock and key. ... Schematic of cell adhesion The study of cell adhesion is part of cell biology. ... Sodium-Potassium pump, an example of Primary active transport secondary active transport Active transport (sometimes called active uptake) is the mediated transport of biochemicals, and other atomic/molecular substances, across membranes. ... The cell cycle, or cell-division cycle, is the series of events that take place in a eukaryotic cell leading to its replication. ...


Lipids

Lipids are the most diverse group of biochemicals. Their main structural uses are as part of biological membranes such as the cell membrane, or as a source of energy.[6] Lipids are usually defined as hydrophobic or amphipathic biological molecules that will dissolve in organic solvents such as benzene or chloroform.[7] The fats are a large group of compounds that contain fatty acids and glycerol; a glycerol molecule attached to three fatty acid esters is a triacylglyceride.[8] Several variations on this basic structure exist, including alternate backbones such as sphingosine in the sphingolipids, and hydrophilic groups such as phosphate in phospholipids. Steroids such as cholesterol are another major class of lipids that are made in cells.[9] Some common lipids. ... A biological membrane or biomembrane is an enclosing or separating tissue which acts as a barrier within or around a cell. ... Look up cell membrane in Wiktionary, the free dictionary. ... Hydrophobe (from the Greek (hydros) water and (phobos) fear) in chemistry refers to the physical property of a molecule that is repelled by water. ... Amphiphile (from the Greek αμφις, amphis: both and φιλíα, philia: love, friendship) is a term describing a chemical compound possessing both hydrophilic and hydrophobic nature. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... For benzine, see petroleum ether. ... R-phrases , , , S-phrases , Flash point Non-flammable U.S. Permissible exposure limit (PEL) 50 ppm (240 mg/m3) (OSHA) Supplementary data page Structure and properties n, εr, etc. ... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... “Glycerine” redirects here. ... A carboxylic acid ester. ... Example of an unsaturated fat triglyceride. ... Sphingosine is a compound that forms a primary part of the sphingolipids, a class of cell membrane lipids which includes sphingomyelin, an important phospholipid. ... General chemical structure of sphingolipids. ... Hydrophile, from the Greek (hydros) water and φιλια (philia) friendship, refers to a physical property of a molecule that can transiently bond with water (H2O) through hydrogen bonding. ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ... Phospholipid Two schematic representations of a phospholipid. ... This article is about the chemical family of steroids. ... Cholesterol is a sterol (a combination steroid and alcohol), a lipid found in the cell membranes of all body tissues, and is transported in the blood plasma of all animals. ...


Carbohydrates

Glucose can exist in both a straight-chain and ring form.
Glucose can exist in both a straight-chain and ring form.

Carbohydrates are straight-chain aldehydes or ketones with many hydroxyl groups that can exist as straight chains or rings. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy (starch, glycogen) and structural components (cellulose in plants, chitin in animals).[6] The basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose. Monosaccharides can be linked together to form polysaccharides in almost limitless ways.[10] Image File history File links Glucose_Fisher_to_Haworth. ... Image File history File links Glucose_Fisher_to_Haworth. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Lactose is a disaccharide found in milk. ... An aldehyde. ... Ketone group A ketone (pronounced as key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... Starch (CAS# 9005-25-8, chemical formula (C6H10O5)n,[1]) is a mixture of amylose and amylopectin (usually in 20:80 or 30:70 ratios). ... This article does not cite any references or sources. ... Cellulose as polymer of β-D-glucose Cellulose in 3D Cellulose (C6H10O5)n is a polysaccharide of beta-glucose. ... Structure of the chitin molecule, showing two of the N-Acetylglucosamine units that repeat to form long chains in beta-1,4 linkage. ... Monosaccharides are the simplest form of carbohydrates. ... Galactose (also called brain sugar) is a type of sugar found in dairy products, in sugar beets and other gums and mucilages. ... Fructose (or levulose) is a simple sugar (monosaccharide) found in many foods and is one of the three most important blood sugars along with glucose and galactose. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ...


Nucleotides

The polymers DNA and RNA are long chains of nucleotides. These molecules are critical for the storage and use of genetic information, through the processes of transcription and protein biosynthesis.[6] This information is protected by DNA repair mechanisms and propagated through DNA replication. A few viruses have an RNA genome, for example HIV, which uses reverse transcription to create a DNA template from its viral RNA genome.[11] RNA in ribozymes such as spliceosomes and ribosomes is similar to enzymes as it can catalyze chemical reactions. Individual nucleosides are made by attaching a nucleobase to a ribose sugar. These bases are heterocyclic rings containing nitrogen, classified as purines or pyrimidines. Nucleotides also act as coenzymes in metabolic group transfer reactions.[12] The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Ribonucleic acid or RNA is a nucleic acid polymer consisting of nucleotide monomers that plays several important roles in the processes that translate genetic information from deoxyribonucleic acid (DNA) into protein products; RNA acts as a messenger between DNA and the protein synthesis complexes known as ribosomes, forms vital portions... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ... An overview of protein synthesis. ... DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... DNA replication. ... This article is about biological infectious particles. ... Species Human immunodeficiency virus 1 Human immunodeficiency virus 2 Human immunodeficiency virus (HIV) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS, a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections). ... Reverse transcriptase is an enzyme used by all retroviruses and retrotransposons that transcribes the genetic information from the virus or retrotransposon from RNA into DNA, which can integrate into the host genome. ... // A ribozyme (from ribonucleic acid enzyme, also called RNA enzyme or catalytic RNA) is an RNA molecule that catalyzes a chemical reaction. ... A spliceosome is a complex of RNA and many protein subunits called snRNPs, that removes the non-coding introns from unprocessed mRNA. Spliceosomes are unique to eukaryotic mRNA as the mRNA of prokaryotes lack introns. ... Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Nucleosides are glycosylamines made by attaching a nucleobase (often reffered to simply as bases) to a ribose ring. ... Adenine Guanine Thymine Cytosine ... Ribose Ribose, primarily seen as D-ribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. ... Heterocyclic compounds are substances which contain a ring structure as found in benzene and the aromatic compounds, or aromatic hydrocarbons, but in which other atoms than carbon, such as sulfur, oxygen or nitrogen are found as part of the ring. ... Purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring that is fused with an imidazole ring. ... Pyrimidine is a heterocyclic aromatic organic compound, which is similar to benzene and pyridine and that contains two nitrogen atoms at positions 1 and 3 of the six-membered ring. ...


Coenzymes

Structure of the coenzyme acetyl-CoA.The transferable acetyl group is bonded to the sulphur atom at the extreme left.
Structure of the coenzyme acetyl-CoA.The transferable acetyl group is bonded to the sulphur atom at the extreme left.

Metabolism involves a vast array of chemical reactions, but most fall under a few basic types of reactions that involve the transfer of functional groups.[13] This common chemistry allows cells to use a small set of metabolic intermediates to carry chemical groups between different reactions.[12] These group-transfer intermediates are called coenzymes. Each class of group-transfer reaction is carried out by a particular coenzyme, which is the substrate for a set of enzymes that produce it, and a set of enzymes that consume it. These coenzymes are therefore continuously being made, consumed and then recycled.[14] Image File history File links Acetyl-CoA-2D.svg‎ Please see the file description page for further information. ... Image File history File links Acetyl-CoA-2D.svg‎ Please see the file description page for further information. ... Coenzyme A Coenzymes are small organic non-protein molecules that carry chemical groups between enzymes. ... Categories: Biochemistry stubs | Thiols ... Acetyl is the radical of acetic acid. ... In organic chemistry, functional groups (or moieties) are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. ... Coenzyme A Coenzymes are small organic non-protein molecules that carry chemical groups between enzymes. ... For other uses, see Substrate. ...


The most central coenzyme is adenosine triphosphate (ATP), the universal energy currency of cells. This nucleotide is used to transfer chemical energy between different chemical reactions. There is only a small amount of ATP in cells, but as it is continuously regenerated, the human body can use about its own weight in ATP per day.[14] ATP acts as a bridge between catabolism and anabolism, with catabolic reactions generating ATP and anabolic reactions consuming it. It also serves as a carrier of phosphate groups in phosphorylation reactions. Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... A phosphorylated serine residue Phosphorylation is the addition of a phosphate (PO4) group to a protein or a small molecule or the introduction of a phosphate group into an organic molecule. ...


A vitamin is an organic compound needed in small quantities that cannot be made in the cells. In human nutrition, most vitamins function as coenzymes after modification; for example, all water-soluble vitamins are phosphorylated or are coupled to nucleotides when they are used in cells.[15] Nicotinamide adenine dinucleotide (NADH), a derivative of vitamin B3 (niacin), is an important coenzyme that acts as a hydrogen acceptor. Hundreds of separate types of dehydrogenases remove electrons from their substrates and reduce NAD+ into NADH. This reduced form of the coenzyme is then a substrate for any of the reductases in the cell that need to reduce their substrates.[16] Nicotinamide adenine dinucleotide exists in two related forms in the cell, NADH and NADPH. The NAD+/NADH form is more important in catabolic reactions, while NADP+/NADPH is used in anabolic reactions. Retinol (Vitamin A) For the record label, see Vitamin Records A vitamin is an organic compound required in tiny amounts for essential metabolic reactions in a living organism. ... The updated USDA food pyramid, published in 2005, is a general nutrition guide for recommended food consumption for humans. ... Nicotinamide adenine dinucleotide (NAD+ or in older notation DPN+) is an important coenzyme found in cells. ... Niacin, also known as nicotinic acid or vitamin B3, is a water-soluble vitamin whose derivatives such as NADH, NAD, NAD+, and NADP play essential roles in energy metabolism in the living cell and DNA repair. ... A dehydrogenase is an enzyme that oxidizes a substrate by transferring one or more protons and a pair of electrons to an acceptor, usually NAD/NADP or a flavin coenzyme such as FAD or FMN. Common examples of dehydrogenase enzymes in the TCA cycle are pyruvate dehydrogenase, isocitrate dehydrogenase, and... Illustration of a redox reaction Redox (shorthand for oxidation/reduction reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... A reductase is an enzyme which lowers the activation energy for a reduction reaction. ...

Structure of hemoglobin. The protein subunits are in red and blue, and the iron-containing heme groups in green. From PDB 1GZX.
Structure of hemoglobin. The protein subunits are in red and blue, and the iron-containing heme groups in green. From PDB 1GZX.

Image File history File links Size of this preview: 600 × 600 pixel Image in higher resolution (1600 × 1600 pixel, file size: 1,006 KB, MIME type: image/png)By Richard Wheeler (Zephyris) 2007. ... Image File history File links Size of this preview: 600 × 600 pixel Image in higher resolution (1600 × 1600 pixel, file size: 1,006 KB, MIME type: image/png)By Richard Wheeler (Zephyris) 2007. ... Structure of hemoglobin. ... Structure of Heme b A heme or haem is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin. ... The Protein Data Bank (PDB) is a repository for 3-D structural data of proteins and nucleic acids. ...

Minerals and cofactors

Further information: Physiology, bioinorganic chemistry and iron metabolism

Inorganic elements play critical roles in metabolism; some are abundant (e.g. sodium and potassium) while others function at minute concentrations. About 99% of mammals' mass are the elements carbon, nitrogen, calcium, sodium, chlorine, potassium, hydrogen, oxygen and sulfur.[17] The organic compounds (proteins, lipids and carbohydrates) contain the majority of the carbon and nitrogen and most of the oxygen and hydrogen is present as water.[17] This article or section does not cite any references or sources. ... Bioinorganic Chemistry is a specialized field that spans the chemistry of metal-containing molecules. ... Human beings use 20 mg of iron each day for the production of new red blood cells, much of which is recycled from old red blood cells. ... For sodium in the diet, see Edible salt. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... For other uses, see Carbon (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... For other uses, see Calcium (disambiguation). ... For sodium in the diet, see Edible salt. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... This article is about the chemical element. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic (see below for more on the definition controversy...


The abundant inorganic elements act as ionic electrolytes. The most important ions are sodium, potassium, calcium, magnesium, chloride, phosphate, and the organic ion bicarbonate. The maintenance of precise gradients across cell membranes maintains osmotic pressure and pH.[18] Ions are also critical for nerves and muscles, as action potentials in these tissues are produced by the exchange of electrolytes between the extracellular fluid and the cytosol.[19] Electrolytes enter and leave cells through proteins in the cell membrane called ion channels. For example, muscle contraction depends upon the movement of calcium, sodium and potassium through ion channels in the cell membrane and T-tubules.[20] This article is about the electrically charged particle. ... An electrolyte is a substance containing free ions that behaves as an electrically conductive medium. ... For sodium in the diet, see Edible salt. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... For other uses, see Calcium (disambiguation). ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... The chloride ion is formed when the element chlorine picks up one electron to form an anion (negatively-charged ion) Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ... For baking soda, see Sodium bicarbonate In inorganic chemistry, a bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. ... An ion gradient is a concentration gradient of ions, it can be called an electrochemical potential gradient of ions across membranes. ... This article or section does not adequately cite its references or sources. ... For other uses, see PH (disambiguation). ... Nerves (yellow) Nerves redirects here. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... In some animals, including mammals, the two types of extracellular fluids are interstitial fluid and blood plasma. ... The cytosol (cf. ... Look up cell membrane in Wiktionary, the free dictionary. ... Ion channels are present in the membranes that surround all biological cells. ... A top-down view of skeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. ... A T-tubule (or Transverse tubule), is a deep invagination of the plasma membrane found in skeletal and cardiac muscle cells. ...


The transition metals are usually present as trace elements in organisms, with zinc and iron being most abundant.[21][22] These metals are used in some proteins as cofactors and are essential for the activity of enzymes such as catalase and oxygen-carrier proteins such as hemoglobin.[23] These cofactors are bound tightly to a specific protein; although enzyme cofactors can be modified during catalysis, cofactors always return to their original state after catalysis has taken place. The metal micronutrients are taken up into organisms by specific transporters and bound to storage proteins such as ferritin or metallothionein when not being used.[24][25] In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... Microminerals (also known as trace elements) are micronutrients that are chemical elements. ... General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... For other uses, see Iron (disambiguation). ... Catalase (human erythrocyte catalase: PDB 1DGF, EC 1. ... Structure of hemoglobin. ... Cofactor may refer to any of the following: Minor (linear algebra) as an alternative name for the determinant of a smaller matrix than that which it describes Cofactor (biochemistry) is a substance that needs to be present in addition to an enzyme for a certain reaction to take place. ... Ferritin is a globular protein found mainly in the liver, which can store about 4500 iron (Fe3+)ions in a hollow protein shell made of 24 subunits. ... Metallothioneins (MTs) is a family of Cys-rich, low molecular weight (MW ranging from 3500 to 14000 Da) proteins. ...


Catabolism

Further information: Catabolism

Catabolism is the set of metabolic processes that release energy. These include breaking down and oxidising food molecules as well as reactions that trap the energy in sunlight. The purpose of these catabolic reactions is to provide the energy and components needed by anabolic reactions. The exact nature of these catabolic reactions differ from organism to organism, with organic molecules being used as a source of energy in organotrophs, while lithotrophs use inorganic substrates and phototrophs capture sunlight as chemical energy. However, all these different forms of metabolism depend on redox reactions that involve the transfer of electrons from reduced donor molecules such as organic molecules, water, ammonia, hydrogen sulfide or ferrous ions to acceptor molecules such as oxygen, nitrate or sulphate.[26] In animals these reactions involve complex organic molecules being broken down to simpler molecules, such as carbon dioxide and water. In photosynthetic organisms such as plants and cyanobacteria, these electron-transfer reactions do not release energy, but are used as a way of storing energy absorbed from sunlight.[6] Anabolism is the aspect of metabolism that contributes to growth. ... This page is a candidate to be copied to Wiktionary. ... A lithotroph is a microorganism which uses an inorganic substrate to synthesize all its organic molecules. ... Phototrophs or photoautotrophs are photosynthetic algae, fungi, bacteria and cyanobacteria which build up carbon dioxide and water into organic cell materials using energy from sunlight. ... Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ... Potential energy can be thought of as energy stored within a physical system. ... Illustration of a redox reaction Redox (shorthand for oxidation/reduction reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... An organic compound is any of a large class of chemical compounds whose molecules contain carbon, with exception of carbides, carbonates and carbon oxides. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... For other uses, see Ammonia (disambiguation). ... Hydrogen sulfide (hydrogen sulphide in British English) is the chemical compound with the formula H2S. This colorless, toxic and flammable gas is responsible for the foul odor of rotten eggs and flatulence. ... Ferrous in chemistry is a term used for the iron with an oxidation number +2. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Trinitrate redirects here. ... Sulfate is the IUPAC name for the SO42- ion, consisting of a central sulfur atom single bonded to four tetrahedrally oriented oxygen atoms. ... An organic compound is any of a large class of chemical compounds whose molecules contain carbon, with exception of carbides, carbonates and carbon oxides. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... The leaf is the primary site of photosynthesis in plants. ... Orders The taxonomy of the Cyanobacteria is currently under revision. ...


The most common set of catabolic reactions in animals can be separated into three main stages. In the first, large organic molecules such as proteins, polysaccharides or lipids are digested into their smaller components outside cells. Next, these smaller molecules are taken up by cells and converted to yet smaller molecules, usually acetyl coenzyme A (CoA), which releases some energy. Finally, the acetyl group on the CoA is oxidised to water and carbon dioxide in the citric acid cycle and electron transport chain, releasing the energy that is stored by reducing the coenzyme nicotinamide adenine dinucleotide (NAD+) into NADH. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ... Some common lipids. ... Coenzyme A (CoA, CoASH, or HSCoA) is a coenzyme, notable for its role in the synthesis and oxidization of fatty acids, and the oxidation of pyruvate in the citric acid cycle. ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... The Electron Transport Chain. ... Nicotinamide adenine dinucleotide (NAD+ or in older notation DPN+) is an important coenzyme found in cells. ...


Digestion

Further information: Digestion and gastrointestinal tract

Macromolecules such as starch, cellulose or proteins cannot be rapidly taken up by cells and need to be broken into their smaller units before they can be used in cell metabolism. Several common classes of enzymes digest these polymers. These digestive enzymes include proteases that digest proteins into amino acids, as well as glycoside hydrolases that digest polysaccharides into monosaccharides. For the industrial process, see anaerobic digestion. ... Upper and Lower gastrointestinal tract The gastrointestinal tract (GI tract), also called the digestive tract, or the alimentary canal, is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. ... Proteases (proteinases, peptidases, or proteolytic enzymes) are enzymes that break peptide bonds between amino acids of proteins. ... Glycoside hydrolases (also called glycosidases) catalyze the hydrolysis of the glycosidic linkage to generate two smaller sugars. ...


Microbes simply secrete digestive enzymes into their surroundings,[27][28] while animals only secrete these enzymes from specialized cells in their guts.[29] The amino acids or sugars released by these extracellular enzymes are then pumped into cells by specific active transport proteins.[30][31] For the Physics term GUT, please refer to Grand unification theory The gastrointestinal or digestive tract, also referred to as the GI tract or the alimentary canal or the gut, is the system of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and... Sodium-Potassium pump, an example of Primary active transport secondary active transport Active transport (sometimes called active uptake) is the mediated transport of biochemicals, and other atomic/molecular substances, across membranes. ...

A simplified outline of the catabolism of proteins, carbohydrates and fats.
A simplified outline of the catabolism of proteins, carbohydrates and fats.

Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Lactose is a disaccharide found in milk. ... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ...

Energy from organic compounds

Further information: Cellular respiration, fermentation, carbohydrate catabolism, fat catabolism and protein catabolism

Carbohydrate catabolism is the breakdown of carbohydrates into smaller units. Carbohydrates are usually taken into cells once they have been digested into monosaccharides.[32] Once inside, the major route of breakdown is glycolysis, where sugars such as glucose and fructose are converted into pyruvate and some ATP is generated.[33] Pyruvate is an intermediate in several metabolic pathways, but the majority is converted to acetyl-CoA and fed into the citric acid cycle. Although some more ATP is generated in the citric acid cycle, the most important product is NADH, which is made from NAD+ as the acetyl-CoA is oxidized. This oxidation releases carbon dioxide as a waste product. In anaerobic conditions, glycolysis produces lactate, through the enzyme lactate dehydrogenase re-oxidizing NADH to NAD+ for re-use in glycolysis. An alternative route for glucose breakdown is the pentose phosphate pathway, which reduces the coenzyme NADPH and produces pentose sugars such as ribose, the sugar component of nucleic acids. Cellular respiration was discovered by mad scientist Mr. ... It has been suggested that this article or section be merged with Fermentation (food). ... Carbohydrate catabolism is the breakdown of carbohydrates into smaller units. ... Fatty acids are an important source of energy for many organisms. ... Protein catabolism is the breakdown of proteins into amino acids and simple derivative compounds, for transport into the cell through the plasma membrane and ultimately for the polymerisation into new proteins via the use of ribonucleic acids (RNA) and ribosomes. ... Monosaccharides are the simplest form of carbohydrates. ... The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Fructose (or levulose) is a simple sugar (monosaccharide) found in many foods and is one of the three most important blood sugars along with glucose and galactose. ... Pyruvic acid (CH3COCO2H) is an alpha-keto acid which plays an important role in biochemical processes. ... Categories: Biochemistry stubs | Thiols ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Lactic acid is a chemical compound that plays a role in several biochemical processes. ... Lactate dehydrogenase (LDH) is an enzyme (EC 1. ... The pentose phosphate pathways Nonoxidative phase The pentose phosphate pathway (also called Phosphogluconate Pathway, or Hexose Monophosphate Shunt [HMP shunt]) is a process that serves to generate NADPH and the synthesis of pentose (5-carbon) sugars. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... A pentose is a monosaccharide with five carbon atoms. ... Ribose Ribose, primarily seen as D-ribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. ... Look up nucleic acid in Wiktionary, the free dictionary. ...


Fats are catabolised by hydrolysis to free fatty acids and glycerol. The glycerol enters glycolysis and the fatty acids are broken down by beta oxidation to release acetyl-CoA, which then is fed into the citric acid cycle. Fatty acids release more energy upon oxidation than carbohydrates because carbohydrates contain more oxygen in their structures. Hydrolysis is a chemical reaction or process in which a chemical compound reacts with water. ... Schematic demonstrating mitochondrial fatty acid beta-oxidation and effects of LCHAD deficiency Beta oxidation is the process by which fatty acids, in the form of Acetyl-CoA molecules, are broken down in the mitochondria to generate Acetyl-CoA, the entry molecule for the Krebs Cycle. ...


Amino acids are either used to synthesize proteins and other biomolecules, or oxidized to urea and carbon dioxide as a source of energy.[34] The oxidation pathway starts with the removal of the amino group by a transaminase. The amino group is fed into the urea cycle, leaving a deaminated carbon skeleton in the form of a keto acid. Several of these keto acids are intermediates in the citric acid cycle, for example the deamination of glutamate forms α-ketoglutarate.[35] The glucogenic amino acids can also be converted into glucose, through gluconeogenesis (discussed below).[36] Phenylalanine is one of the standard amino acids. ... Urea is an organic compound with the chemical formula (NH2)2CO. Urea is also known as carbamide, especially in the recommended International Nonproprietary Names (rINN) in use in Europe. ... In biochemistry, a transaminase or an aminotransferase is an enzyme that catalyzes a type of reaction between an amino acid and an α-keto acid. ... The reactions of the urea cycle. ... Keto acids are organic acids containing a ketone functional group and a carboxylic acid group. ... Glutamate is the anion of glutamic acid. ... Ketoglutaric acid is used for either of two crystalline keto derivatives C5H6O5 of glutaric acid. ... A glucogenic amino acid is an amino acid that can be converted into glucose through gluconeogenesis. ... Pyruvic acid Oxaloacetic acid Phosphoenolpyruvate Fructose 1,6-bisphosphate Fructose 6-phosphate Glucose-6-phosphate Glucose Gluconeogenesis is the generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and amino acids (primarily alanine and glutamine). ...


Oxidative phosphorylation

Structure of ATP synthase, the proton channel and rotating stalk are shown in blue and the synthase subunits in red.
Further information: Oxidative phosphorylation, chemiosmosis and mitochondrion

In oxidative phosphorylation, the electrons removed from food molecules in pathways such as the citric acid cycle are transferred to oxygen and the energy released used to make ATP. This is done in eukaryotes by a series of proteins in the membranes of mitochondria called the electron transport chain. In prokaryotes, these proteins are found in the cell's inner membrane.[37] These proteins use the energy released from passing electrons from reduced molecules like NADH onto oxygen to pump protons across a membrane.[38] Image File history File links Size of this preview: 431 × 599 pixelsFull resolution (461 × 641 pixel, file size: 278 KB, MIME type: image/png) Modified version of December 2005 PDB Molecule of the Month by David S. Goodsell link File historyClick on a date/time to view the file as... Image File history File links Size of this preview: 431 × 599 pixelsFull resolution (461 × 641 pixel, file size: 278 KB, MIME type: image/png) Modified version of December 2005 PDB Molecule of the Month by David S. Goodsell link File historyClick on a date/time to view the file as... An ATP synthase (EC 3. ... The Electron Transport Chain. ... Chemiosmosis is the diffusion of ions across a membrane. ... Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed organelle that is found in most eukaryotic cells. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... The Electron Transport Chain. ... Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... Bacteria, despite their apparent simplicity contain a well developed cell structure which is responsible for many of their unique biological properties. ... A reducing agent (also called a reductant or reducer) is the element or a compound in a redox (reduction-oxidation) reaction (see electrochemistry) that reduces another species. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... For other uses, see Proton (disambiguation). ...


Pumping protons out of the mitochondria creates a proton concentration difference across the membrane and generates a electrochemical gradient.[39] This force drives protons back into the mitochondrion through the base of an enzyme called ATP synthase. The flow of protons makes the stalk subunit rotate, causing the active site of the synthase domain to change shape and phosphorylate adenosine diphosphate - turning it into ATP.[14] diffusion (disambiguation). ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ... An ATP synthase (EC 3. ... The active site of an enzyme is the binding site where catalysis occurs. ... Adenosine diphosphate, abbreviated ADP, is a nucleotide. ...


Energy from inorganic compounds

Further information: Microbial metabolism and nitrogen cycle

Chemolithotrophy is a type of metabolism found in prokaryotes where energy is obtained from the oxidation of inorganic compounds. These organisms can use hydrogen,[40] reduced sulfur compounds (such as sulfide, hydrogen sulfide and thiosulfate),[41] ferrous iron (FeII)[42] or ammonia[43] as sources of reducing power and they gain energy from the oxidation of these compounds with electron acceptors such as oxygen or nitrite.[44] These microbial processes are important in global biogeochemical cycles such as acetogenesis, nitrification and denitrification and are critical for soil fertility.[45][46] Microbial metabolism is the means by which a microbe obtains energy and the nutrients (e. ... Schematic representation of the flow of Nitrogen through the environment. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... An inorganic compound is a chemical compound not containing carbon and hydrogen atoms bonded to each other. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... This article is about the chemical element. ... Formally, sulfide is the dianion, S2−, which exists in strongly alkaline aqueous solutions formed from H2S or alkali metal salts such as Li2S, Na2S, and K2S. Sulfide is exceptionally basic and, with a pKa > 14, it does not exist in appreciable concentrations even in highly alkaline water. ... Hydrogen sulfide (hydrogen sulphide in British English) is the chemical compound with the formula H2S. This colorless, toxic and flammable gas is responsible for the foul odor of rotten eggs and flatulence. ... It has been suggested that thiosulfate ion be merged into this article or section. ... Iron(II) oxide, also called ferrous oxide, is a black-colored powder with the chemical formula FeO. It consists of the element iron in the oxidation state of 2 bonded to oxygen. ... For other uses, see Ammonia (disambiguation). ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... // Definition The nitrite ion is NO2−. A nitrite compound is one that contains this group, either an ionic compound, or an analogous covalent one. ... In ecology, a biogeochemical cycle is a circuit where a nutrient moves back and forth between both biotic and abiotic components of ecosystems. ... Acetogenesis is a process through which acetate is produced by anaerobic bacteria from a variety of energy (for example, hydrogen) and carbon (for example, carbon dioxide) sources. ... Nitrogen cycle Nitrification is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates. ... This does not cite its references or sources. ... Soil fertility is the characteristic of soil that supports abundant plant life. ...


Energy from light

Further information: Phototroph, photophosphorylation, chloroplast

The energy in sunlight is captured by plants, cyanobacteria, purple bacteria, green sulfur bacteria and some protists. This process is often coupled to the conversion of carbon dioxide into organic compounds, as part of photosynthesis, which is discussed below. The energy capture and carbon fixation systems can however operate separately in prokaryotes, as purple bacteria and green sulfur bacteria can use sunlight as a source of energy, while switching between carbon fixation and the fermentation of organic compounds.[47][48] Phototrophs or photoautotrophs are photosynthetic algae, fungi, bacteria and cyanobacteria which build up carbon dioxide and water into organic cell materials using energy from sunlight. ... The production of ATP using the energy of sunlight is called photophosphorylation. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... u fuck in ua ... Orders The taxonomy of the Cyanobacteria is currently under revision. ... Purple bacteria or purple photosynthetic bacteria are proteobacteria that are phototrophic, i. ... Green sulfur bacteria - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Typical phyla Chromalveolata Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Cabozoa Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: (RP); (GenAm)), Greek protiston -a meaning the (most) first of all...


The capture of solar energy is a process that is similar in principle to oxidative phosphorylation, as it involves energy being stored as a proton concentration gradient and this proton motive force then driving ATP synthesis.[14] The electrons needed to drive this electron transport chain come from light-gathering proteins called photosynthetic reaction centres. These structures are classed into two types depending on the type of photosynthetic pigment present, with most photosynthetic bacteria only having one type of reaction center, while plants and cyanobacteria have two.[49] An electron micrograph of a series of reaction centers and light harvesting complexes from the surface of the thylakoid membrane inside a chloroplast. ... It has been suggested that Photosynthetic Pigments be merged into this article or section. ...


In plants, photosystem II uses light energy to remove electrons from water, releasing oxygen as a waste product. The electrons then flow to the cytochrome b6f complex, which uses their energy to pump protons across the thylakoid membrane in the chloroplast.[50] These protons move back through the membrane as they drive the ATP synthase, as before. The electrons then flow through photosystem I and can then either be used to reduce the coenzyme NADP+, for use in the Calvin cycle which is discussed below, or recycled for further ATP generation.[51] REDIRECT [[In the process of photosynthesis, light is absorbed by a photosystem (ancient Greek: phos = light and systema = assembly) to begin an energy-producing reaction. ... The cytochrome b6f complex (plastoquinol—plastocyanin reductase; EC 1. ... Thylakoids (green) inside a chloroplast Thylakoids (green) inside a cyanobacterium (Synechocystis) A Thylakoid is a membrane-bound compartment inside chloroplasts and cyanobacteria. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... REDIRECT [[In the process of photosynthesis, light is absorbed by a photosystem (ancient Greek: phos = light and systema = assembly) to begin an energy-producing reaction. ... Overview of the Calvin cycle and carbon fixation The Calvin cycle (or Calvin-Benson cycle or carbon fixation) is a series of biochemical reactions that takes place in the stroma of chloroplasts in photosynthetic organisms. ...


Anabolism

Further information: Anabolism

Anabolism is the set of constructive metabolic processes where the energy released by catabolism is used to synthesize complex molecules. In general, the complex molecules that make up cellular structures are constructed step-by-step from small and simple precursors. Anabolism involves three basic stages. Firstly, the production of precursors such as amino acids, monosaccharides, isoprenoids and nucleotides, secondly, their activation into reactive forms using energy from ATP, and thirdly, the assembly of these precursors into complex molecules such as proteins, polysaccharides, lipids and nucleic acids. Anabolism is the metabolic process that builds larger molecules from smaller ones. ... Phenylalanine is one of the standard amino acids. ... Monosaccharides are the simplest form of carbohydrates. ... Chemical structure of the terpenoid isopentenyl pyrophosphate. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ... Some common lipids. ... Look up nucleic acid in Wiktionary, the free dictionary. ...


Organisms differ in how many of the molecules in their cells they can construct for themselves. Autotrophs such as plants can construct the complex organic molecules in cells such as polysaccharides and proteins from simple molecules like carbon dioxide and water. Heterotrophs, on the other hand, require a source of more complex substances, such as monosaccharides and amino acids, to produce these complex molecules. Organisms can be further classified by ultimate source of their energy: photoautotrophs and photoheterotrophs obtain energy from light, whereas chemoautotrophs and chemoheterotrophs obtain energy from inorganic oxidation reactions. Green (from chlorophyll) fronds of a maidenhair fern: a photoautotroph Flowchart to determine if a species is autotroph, heterotroph, or a subtype An autotroph (from the Greek autos = self and trophe = nutrition) is an organism that produces complex organic compounds from simple inorganic molecules and an external source of energy... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Flowchart to determine if a species is autotroph, heterotroph, or a subtype A heterotroph (Greek heterone = (an)other and trophe = nutrition) is an organism that requires organic substrates to get its carbon for growth and development. ...


Carbon fixation

Further information: Photosynthesis, carbon fixation and chemosynthesis
Plant cells (bounded by purple walls) filled with chloroplasts (green), which are the site of photosynthesis.
Plant cells (bounded by purple walls) filled with chloroplasts (green), which are the site of photosynthesis.

Photosynthesis is the synthesis of glucose from sunlight, carbon dioxide (CO2) and water, with oxygen produced as a waste product. This process uses the ATP and NADPH produced by the photosynthetic reaction centres, as described above, to convert CO2 into glycerate 3-phosphate, which can then be converted into glucose. This carbon-fixation reaction is carried out by the enzyme RuBisCO as part of the Calvin – Benson cycle.[52] Three types of photosynthesis occur in plants, C3 carbon fixation, C4 carbon fixation and CAM photosynthesis. These differ by the route that carbon dioxide takes to the Calvin cycle, with C3 plants fixing CO2 directly, while C4 and CAM photosynthesis incorporate the CO2 into other compounds first, as adaptations to deal with intense sunlight and dry conditions.[53] The leaf is the primary site of photosynthesis in plants. ... Carbon fixation is a process found in autotrophs, usually driven by photosynthesis, whereby carbon dioxide is converted into organic compounds. ... Chemosynthesis is the biological conversion of 1-carbon molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic molecules (e. ... Image File history File linksMetadata No higher resolution available. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... An electron micrograph of a series of reaction centers and light harvesting complexes from the surface of the thylakoid membrane inside a chloroplast. ... Glycerate 3-phosphate (GP) or 3-phosphoglycerate (3PG). ... Ribulose-1,5-bisphosphate carboxylase/oxygenase, most commonly known by the shorter name RuBisCO, is an enzyme (EC 4. ... Overview of the Calvin cycle and carbon fixation The Calvin cycle (or Calvin-Benson cycle or carbon fixation) is a series of biochemical reactions that takes place in the stroma of chloroplasts in photosynthetic organisms. ... C3 carbon fixation is a pathway for carbon fixation in photosynthesis. ... Overview of C4 carbon fixation C4 carbon fixation is one of three methods, along with C3 and CAM photosynthesis, used by land plants to fix carbon dioxide (binding the gaseous molecules to dissolved compounds inside the plant) for sugar production through photosynthesis. ... Crassulacean Acid Metabolism (CAM) is a carbon fixation pathway in some photosynthetic plants. ...


In photosynthetic prokaryotes the mechanisms of carbon fixation are more diverse. Here, carbon dioxide can be fixed by the Calvin – Benson cycle, a reversed citric acid cycle,[54] or the carboxylation of acetyl-CoA.[55][56] Prokaryotic chemoautotrophs also fix CO2 through the Calvin – Benson cycle, but use energy from inorganic compounds to drive the reaction.[57] Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... reverse krebs cycle ... Flowchart to determine if a species is autotroph, heterotroph, or a subtype Chemotrophs are organisms that obtain energy by the oxidation of electron donating molecules in their environments. ...


Carbohydrates and glycans

Further information: Gluconeogenesis, glyoxylate cycle, glycogenesis and glycosylation

In carbohydrate anabolism, simple organic acids can be converted into monosaccharides such as glucose and then used to assemble polysaccharides such as starch. The generation of glucose from compounds like pyruvate, lactate, glycerol, glycerate 3-phosphate and amino acids is called gluconeogenesis. Gluconeogenesis converts pyruvate to glucose-6-phosphate through a series of intermediates, many of which are shared with glycolysis.[33] However, this pathway is not simply glycolysis run in reverse, as several steps are catalyzed by non-glycolytic enzymes. This is important as it allows the formation and breakdown of glucose to be regulated separately and prevents both pathways from running simultaneously in a futile cycle.[58][59] Pyruvic acid Oxaloacetic acid Phosphoenolpyruvate Fructose 1,6-bisphosphate Fructose 6-phosphate Glucose-6-phosphate Glucose Gluconeogenesis is the generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and amino acids (primarily alanine and glutamine). ... Overview of the Glyoxylate Cycle The glyoxylate cycle is a metabolic pathway occurring in plants, certain vertebrates, and several microorganisms, such as E. coli and yeast. ... Glycogenesis is the process of glycogen synthesis, in which glucose molecules are added to chains of glycogen. ... Glycosylation is the process or result of addition of saccharides to proteins and lipids. ... Monosaccharides are the simplest form of carbohydrates. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ... Starch (CAS# 9005-25-8, chemical formula (C6H10O5)n,[1]) is a mixture of amylose and amylopectin (usually in 20:80 or 30:70 ratios). ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Pyruvate (CH3COCOO−) is the ionized form of pyruvic acid. ... Lactic acid is a chemical compound that plays a role in several biochemical processes. ... “Glycerine” redirects here. ... Glycerate 3-phosphate (GP) or 3-phosphoglycerate (3PG). ... In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ... Pyruvic acid Oxaloacetic acid Phosphoenolpyruvate Fructose 1,6-bisphosphate Fructose 6-phosphate Glucose-6-phosphate Glucose Gluconeogenesis is the generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and amino acids (primarily alanine and glutamine). ... Glucose 6-phosphate is glucose sugar phosphorylated on carbon 6. ... The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... A Futile cycle is when two metabolic pathways run simultaneously in opposite directions and have no overall effect other than wasting energy. ...


Although fat is a common way of storing energy, in vertebrates such as humans the fatty acids in these stores cannot be converted to glucose through gluconeogenesis as these organisms cannot convert acetyl-CoA into pyruvate.[60] As a result, after long-term starvation, vertebrates need to produce ketone bodies from fatty acids to replace glucose in tissues such as the brain that cannot metabolize fatty acids.[61] In other organisms such as plants and bacteria, this metabolic problem is solved using the glyoxylate cycle, which bypasses the decarboxylation step in the citric acid cycle and allows the transformation of acetyl-CoA to oxaloacetate, where it can be used for the production of glucose.[62][60] This article does not cite any references or sources. ... This article is about modern humans. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... Pyruvic acid Oxaloacetic acid Phosphoenolpyruvate Fructose 1,6-bisphosphate Fructose 6-phosphate Glucose-6-phosphate Glucose Gluconeogenesis is the generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and amino acids (primarily alanine and glutamine). ... Pyruvate (CH3COCOO−) is the ionized form of pyruvic acid. ... Ketone bodies are three chemicals that are produced as by-products when fatty acids are broken down for energy. ... Overview of the Glyoxylate Cycle The glyoxylate cycle is a metabolic pathway occurring in plants, certain vertebrates, and several microorganisms, such as E. coli and yeast. ... A Decarboxylation is any chemical reaction in which a carboxyl group (-COOH) is split off from a compound as carbon dioxide (CO2). ...


Polysaccharides and glycans are made by the sequential addition of monosaccharides by glycosyltransferase from a reactive sugar-phosphate donor such as uridine diphosphate glucose (UDP-glucose) to an acceptor hydroxyl group on the growing polysaccharide. As any of the hydroxyl groups on the ring of the substrate can be acceptors, the polysaccharides produced can have straight or branched structures.[63] The polysaccharides produced can have structural or metabolic functions themselves, or be transferred to lipids and proteins by enzymes called oligosaccharyltransferases.[64][65] Glycans are polysaccharides. ... Glycosyltransferases are a group of enzymes that act as a catalyst for the transfer of a monosaccharide from a glycosylamine derivative to an acceptor. ... Uridine diphosphate glucose, sometimes called uracil-diphosphate glucose and abbreviated UDP-glucose, is a nucleotide. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... Oligosaccharyltransferase or OST (EC 2. ...


Fatty acids, isoprenoids and steroids

Further information: Fatty acid synthesis, mevalonate pathway and non-mevalonate pathway
Simplified version of the steroid synthesis pathway with the intermediates isopentenyl pyrophosphate (IPP), dimethylallyl pyrophosphate (DMAPP), geranyl pyrophosphate (GPP) and squalene shown. Some intermediates are omitted for clarity.
Simplified version of the steroid synthesis pathway with the intermediates isopentenyl pyrophosphate (IPP), dimethylallyl pyrophosphate (DMAPP), geranyl pyrophosphate (GPP) and squalene shown. Some intermediates are omitted for clarity.

Fatty acids are made by fatty acid synthases that polymerize and reduce acetyl-CoA units. The acyl chains in the fatty acids are extended by a cycle of reactions that add the actyl group, reduce it to the alcohol, dehydrate it to an alkene group and then reduce it again to an alkane group. The enzymes of fatty acid biosynthesis are divided into two groups, in animals and fungi all these fatty acid synthase reactions are carried out by a single multifunctional type I protein,[66] while in plant plastids and bacteria separate type II enzymes perform each step in the pathway.[67][68] Fatty acids are formed by the action of Fatty acid synthases from acetyl-CoA and malonyl-CoA precursors. ... The mevalonate pathway or HMG-CoA reductase pathway or mevalonate-dependent (MAD) route, is an important cellular metabolic pathway present in all higher eukaryotes and many bacteria. ... The non-mevalonate pathway or 2-C-methyl-D-erythritol 4-phosphate/1-deoxy-D-xylulose 5-phosphate pathway (MEP/DOXP pathway) of isoprenoid biosynthesis is an alternative metabolic pathway leading to the formation of isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) that has been elucidated only recently. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Chemical structure of isopentenyl pyrophosphate. ... Structure of dimethyallyl pyrophosphate Dimethylallyl pyrophosphate (or -diphosphate) (DMAPP) is an intermediate product of both mevalonic acid (MVA) pathway and DOXP/MEP pathway. ... Chemical structure of geranyl pyrophosphate. ... Squalene is a natural organic compound originally obtained for commercial purposes primarily from shark liver oil, though there are botanic sources as well, including amaranth seed, rice bran, wheat germ, and olives. ... Fatty acids are aliphatic acids fundamental to energy production and storage, cellular structure and as intermediates in the biosynthesis of hormones and other biologically important molecules. ... In chemistry, a dehydration reaction is a chemical reaction that involves the loss of water from the reacting molecule. ... The chemical structure of ethylene, the simplest alkene. ... Chemical structure of methane, the simplest alkane Alkanes are chemical compounds that consist only of the elements carbon (C) and hydrogen (H) (i. ... Plant cells with visible chloroplasts. ...


Terpenes and isoprenoids are a large class of lipids that include the carotenoids and form the largest class of plant natural products.[69] These compounds are made by the assembly and modification of isoprene units donated from the reactive precursors isopentenyl pyrophosphate and dimethylallyl pyrophosphate.[70] These precursors can be made in different ways. In animals and archaea, the mevalonate pathway produces these compounds from acetyl-CoA,[71] while in plants and bacteria the non-mevalonate pathway uses pyruvate and glyceraldehyde 3-phosphate as substrates.[72][70] One important reaction that uses these activated isoprene donors is steroid biosynthesis. Here, the isoprene units are joined together to make squalene and then folded up and formed into a set of rings to make lanosterol.[73] Lanosterol can then be converted into other steroids such as cholesterol and ergosterol.[74][73] Many terpenes are derived from conifer resins, here a pine. ... Chemical structure of the terpenoid isopentenyl pyrophosphate. ... The orange ring surrounding Grand Prismatic Spring is due to carotenoid molecules, produced by huge mats of algae and bacteria. ... Secondary metabolites, also known as natural products, are those products (chemical compounds) of metabolism that are not essential for normal growth, development or reproduction of an organism. ... Isoprene is a common synonym for the chemical compound 2-methyl-1,3-butadiene. ... Chemical structure of isopentenyl pyrophosphate. ... Structure of dimethyallyl pyrophosphate Dimethylallyl pyrophosphate (or -diphosphate) (DMAPP) is an intermediate product of both mevalonic acid (MVA) pathway and DOXP/MEP pathway. ... The mevalonate pathway or HMG-CoA reductase pathway or mevalonate-dependent (MAD) route, is an important cellular metabolic pathway present in all higher eukaryotes and many bacteria. ... The non-mevalonate pathway or 2-C-methyl-D-erythritol 4-phosphate/1-deoxy-D-xylulose 5-phosphate pathway (MEP/DOXP pathway) of isoprenoid biosynthesis is an alternative metabolic pathway leading to the formation of isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) that has been elucidated only recently. ... G3P (structure) Glyceraldehyde 3-phosphate (G3P) is an intermediate in both glycolysis and gluconeogenesis. ... This article is about the chemical family of steroids. ... Squalene is a natural organic compound originally obtained for commercial purposes primarily from shark liver oil, though there are botanic sources as well, including amaranth seed, rice bran, wheat germ, and olives. ... Lanosterol is a tetracyclic triterpenoid which is the compound from which all steroids are derived. ... Cholesterol is a sterol (a combination steroid and alcohol), a lipid found in the cell membranes of all body tissues, and is transported in the blood plasma of all animals. ... Ergosterol (ergosta-5,7,22-trien-3β-ol), a sterol, is the biological precursor to Vitamin D2. ...


Proteins

Further information: Protein biosynthesis, Amino acid synthesis

Organisms vary in their ability to synthesize the 20 common amino acids. Most bacteria and plants can synthesize all twenty, but mammals can synthesize only the ten nonessential amino acids.[6] Thus, the essential amino acids must be obtained from food. All amino acids are synthesized from intermediates in glycolysis, the citric acid cycle, or the pentose phosphate pathway. Nitrogen is provided by glutamate and glutamine. Amino acid synthesis depends on the formation of the appropriate alpha-keto acid, which is then transaminated to form an amino acid.[75] An overview of protein synthesis. ... For the non-biological synthesis of amino acids see: Strecker amino acid synthesis Amino acid synthesis is the set of biochemical processes (metabolic pathways) by which the various amino acids are produced from other compounds. ... An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo by the organism (usually referring to humans), and therefore must be supplied in the diet. ... Glutamate is the anion of glutamic acid. ... Glutamine is one of the 20 amino acids encoded by the standard genetic code. ... In biochemistry, a transaminase or an aminotransferase is an enzyme that catalyzes a type of reaction between an amino acid and an α-keto acid. ...


Amino acids are made into proteins by being joined together in a chain by peptide bonds. Each different protein has a unique sequence of amino acid residues: this is its primary structure. Just as the letters of the alphabet can be combined to form an almost endless variety of words, amino acids can be linked in varying sequences to form a huge variety of proteins. Proteins are made from amino acids that have been activated by attachment to a transfer RNA molecule through an ester bond. This aminoacyl-tRNA precursor is produced in an ATP-dependent reaction carried out by an aminoacyl tRNA synthetase.[76] This aminoacyl-tRNA is then a substrate for the ribosome, which joins the amino acid onto the elongating protein chain, using the sequence information in a messenger RNA.[77] A peptide bond is a chemical bond that is formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (H2O). ... A protein primary structure is a chain of amino acids. ... Transfer RNA Transfer RNA (abbreviated tRNA), first hypothesized by Francis Crick, is a small RNA chain (73-93 nucleotides) that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. ... A carboxylic acid ester. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... An aminoacyl tRNA synthetase (abbreviated aaRs) is an enzyme that catalyzes the binding of a specific amino acid to a tRNA to form an aminoacyl-tRNA. The synthetase hydrolyzes ATP to bind the appropriate amino acid to the 3 hydroxyl of the tRNA molecule. ... Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... The life cycle of an mRNA in a eukaryotic cell. ...


Nucleotide synthesis and salvage

Further information: Nucleotide salvage, Pyrimidine biosynthesis, and Purine metabolism

Nucleotides are made from amino acids, carbon dioxide and formic acid in pathways that require large amounts of metabolic energy.[78] Consequently, most organisms have efficient systems to salvage preformed nucleotides.[78][79] Purines are synthesized as nucleosides (bases attached to ribose). Both adenine and guanine are made from the precursor nucleoside inosine monophosphate, which is synthesized using atoms from the amino acids glycine, glutamine, and aspartic acid, as well as formate transferred from the coenzyme tetrahydrofolate. Pyrimidines, on the other hand, are synthesized from the base orotate, which is formed from glutamine and aspartate.[80] A salvage pathway is a pathway in which nucleotides (purine and pyrimidine) are synthesized from intermediates in the degradative pathway for nucleotides. ... Pyrimidine biosynthesis occurs both in the body and through organic synthesis. ... Purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. ... Formic acid (systematically called methanoic acid) is the simplest carboxylic acid. ... Purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. ... Nucleosides are glycosylamines made by attaching a nucleobase (often reffered to simply as bases) to a ribose ring. ... Ribose Ribose, primarily seen as D-ribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. ... For the programming language Adenine, see Adenine (programming language). ... Guanine is one of the five main nucleobases found in the nucleic acids DNA and RNA; the others being adenine, cytosine, thymine, and uracil. ... Inosine is a molecule (known as a nucleoside) that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N9-glycosidic bond. ... For the plant, see Glycine (plant). ... Glutamine is one of the 20 amino acids encoded by the standard genetic code. ... Aspartic acid (abbreviated as Asp or D; Asx or B represent either aspartic acid or asparagine[1] ) is an α-amino acid with the chemical formula HO2CCH(NH2)CH2CO2H. The L-isomer is a protonated varient of one of the 20 proteinogenic amino acids, i. ... Formate or methanoate is the ion is HCOO- (formic acid minus one hydrogen ion). ... Coenzyme A Coenzymes are small organic non-protein molecules that carry chemical groups between enzymes. ... Folic acid and folate (the anion form) are forms of the water-soluble Vitamin B9. ... Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring [1]. It is isomeric with two other forms of diazine. ... Wikipedia does not yet have an article with this exact name. ...


Xenobiotics and redox metabolism

Further information: Detoxification, Drug metabolism and Antioxidants

All organisms are constantly exposed to compounds that they cannot use as foods and would be harmful if they accumulated in cells, as they have no metabolic function. These potentially damaging compounds are called xenobiotics.[81] Xenobiotics such as synthetic drugs, natural poisons and antibiotics are detoxified by a set of xenobiotic-metabolizing enzymes. In humans, these include cytochrome P450 oxidases,[82] UDP-glucuronosyltransferasess,[83] and glutathione S-transferases.[84] This system of enzymes acts in three stages to firstly oxidize the xenobiotic (phase I) and then conjugate water-soluble groups onto the molecule (phase II). The modified water-soluble xenobiotic can then be pumped out of cells and in multicellular organisms may be further metabolized before being excreted (phase III). In ecology, these reactions are particularly important in microbial biodegradation of pollutants and the bioremediation of contaminated land and oil spills.[85] Many of these microbial reactions are shared with multicellular organisms, but due to their incredible diversity, microbes are able to deal with a far wider range of xenobiotics than multicellular organisms and can degrade even persistent organic pollutants such as organochloride compounds.[86] Detox, short for detoxification, in general is the removal of toxic substances from the body. ... Drug metabolism is the metabolism of drugs, their biochemical modification or degradation, usually through specialized enzymatic systems. ... Space-filling model of the antioxidant metabolite glutathione. ... A xenobiotic is a chemical which is found in an organism but which is not normally produced or expected to be present in it. ... For other meanings, see Drug (disambiguation). ... The skull and crossbones symbol (Jolly Roger) traditionally used to label a poisonous substance. ... Staphylococcus aureus - Antibiotics test plate. ... Cytochrome P450 Oxidase (CYP2E1) Cytochrome P450 oxidase (commonly abbreviated CYP) is a generic term for a large number of related, but distinct, oxidative enzymes (EC 1. ... Uridine 5-diphospho-glucuronosyltransferase (UDP-glucuronosyltransferase, UGT) is a naturally-occurring enzyme (EC 2. ... This article or section is in need of attention from an expert on the subject. ... For the journal, see Ecology (journal). ... Biodegradation is the process by which organic substances are broken down by living organisms. ... Bioremediation can be defined as any process that uses microorganisms, fungi, green plants or their enzymes to return the environment altered by contaminants to its original condition. ... Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. ... An organochloride, organochlorine or chlorocarbon, is an organic compound containing at least one covalently bonded chlorine atom. ...


A related problem for aerobic organisms is oxidative stress.[87] Here, processes including oxidative phosphorylation and the formation of disulfide bonds during protein folding produce reactive oxygen species such as hydrogen peroxide.[88] These damaging oxidants are removed by antioxidant metabolites such as glutathione and enzymes such as catalases and peroxidases.[89][90] Aerobic and anaerobic bacteria can be identified by growning them in liquid culture: 1: Obligate aerobic bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen. ... Oxidative stress is a medical term for damage to animal or plant cells (and thereby the organs and tissues composed of those cells) caused by reactive oxygen species, which include (but are not limited to) superoxide, singlet oxygen, peroxynitrite or hydrogen peroxide. ... The Electron Transport Chain. ... In chemistry, a disulfide bond is a single covalent bond derived from the coupling of thiol groups. ... Protein folding is the process by which a protein assumes its characteristic functional shape or tertiary structure, also known as the native state. ... Reactive oxygen species (ROS) include oxygen ions, free radicals and peroxides both inorganic and organic. ... R-phrases , , , , S-phrases , , , ,, , , , Flash point Non-flammable Related Compounds Related compounds Water Ozone Hydrazine Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in... Space-filling model of the antioxidant metabolite glutathione. ... Glutathione (GSH) is a tripeptide. ... Catalase (human erythrocyte catalase: PDB 1DGF, EC 1. ... Glutathione Peroxidase 1 A peroxidase (eg. ...


Thermodynamics of living organisms

Further information: Biological thermodynamics

Living organisms must obey the laws of thermodynamics, which describe the transfer of heat and work. The second law of thermodynamics states that in any closed system, the amount of entropy (disorder) will tend to increase. Although living organisms' amazing complexity appears to contradict this law, life is possible as all organisms are open systems that exchange matter and energy with their surroundings. Thus living systems are not in equilibrium, but instead are dissipative systems that maintain their state of high complexity by causing a larger increase in the entropy of their environments.[91] The metabolism of a cell achieves this by coupling the spontaneous processes of catabolism to the non-spontaneous processes of anabolism. In thermodynamic terms, metabolism maintains order by creating disorder.[92] This article is about the study of energy transformation in Biology and related subjects. ... The laws of thermodynamics, in principle, describe the specifics for the transport of heat and work in thermodynamic processes. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... In thermodynamics, work is the quantity of energy transferred from one system to another without an accompanying transfer of entropy. ... The second law of thermodynamics is an expression of the universal law of increasing entropy. ... In thermodynamics, a closed system, as contrasted with an isolated system, can exchange heat and work, but not matter, with its surroundings. ... For a less technical and generally accessible introduction to the topic, see Introduction to entropy. ... This article is about systems theory. ... In thermodynamics, a thermodynamic system is said to be in thermodynamic equilibrium when it is in thermal equilibrium, mechanical equilibrium, and chemical equilibrium. ... A dissipative system (or dissipative structure) is an open system which is operating far from thermodynamic equilibrium within an environment that exchanges energy, matter or entropy. ... A spontaneous process in chemical reaction terms is one which occurs with the system releasing free energy in some form (often, but not always, heat) and moving to a lower energy, hence more thermodynamically stable, state. ... Non-equilibrium thermodynamics is a branch of thermodynamics concerned with studying time-dependent thermodynamic systems, irreversible transformations and open systems. ...


Regulation and control

Further information: Metabolic pathway, metabolic control analysis, hormone and cell signaling

As the environments of most organisms are constantly changing, the reactions of metabolism must be finely regulated to maintain a constant set of conditions within cells, a condition called homeostasis.[93][94] Metabolic regulation also allows organisms to respond to signals and interact actively with their environments.[95] Two closely-linked concepts are important for understanding how metabolic pathways are controlled. Firstly, the regulation of an enzyme in a pathway is how its activity is increased and decreased in response to signals. Secondly, the control exerted by this enzyme is the effect that these changes in its activity have on the overall rate of the pathway (the flux through the pathway).[96] For example, an enzyme may show large changes in activity (i.e. it is highly regulated) but if these changes have little effect on the flux of a metabolic pathway, then this enzyme is not involved in the control of the pathway.[97] In biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell. ... Metabolic control analysis is a computational method for analysing variation in fluxes and intermediate concentrations in a metabolic pathway relating to the effects of the different enzymes that constitute the pathway. ... Norepinephrine A hormone (from Greek όρμή - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... Cell signaling is part of a complex system of communication that governs basic cellular activities and coordinates cell actions. ... Homeostasis is the property of either an open system or a closed system,[1] especially a living organism, to regulate its internal environment to maintain a stable, constant condition. ... flux in science and mathematics. ...

Effect of insulin on glucose uptake and metabolism. Insulin binds to its receptor (1) which in turn starts many protein activation cascades (2). These include: translocation of Glut-4 transporter to the plasma membrane and influx of glucose (3), glycogen synthesis (4), glycolysis (5) and fatty acid synthesis (6).

There are multiple levels of metabolic regulation. In intrinsic regulation, the metabolic pathway self-regulates to respond to changes in the levels of substrates or products; for example, a decrease in the amount of product can increase the flux through the pathway to compensate.[96] This type of regulation often involves allosteric regulation of the activities of multiple enzymes in the pathway.[98] Extrinsic control involves a cell in a multicellular organism changing its metabolism in response to signals from other cells. These signals are usually in the form of soluble messengers such as hormones and growth factors and are detected by specific receptors on the cell surface.[99] These signals are then transmitted inside the cell by second messenger systems that often involved the phosphorylation of proteins.[100] Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... This article does not cite any references or sources. ... The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... flux in science and mathematics. ... In biochemistry, allosteric regulation is the regulation of an enzyme or protein by binding an effector molecule at the proteins allosteric site (that is, a site other than the proteins active site). ... Norepinephrine A hormone (from Greek όρμή - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... Growth factor is a protein that acts as a signaling molecule between cells (like cytokines and hormones) that attaches to specific receptors on the surface of a target cell and promotes differentiation and maturation of these cells. ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ... In cell physiology, a secondary messenger system (also known as a second messenger system) is a method of cellular signalling where the signalling molecule does not enter the cell, but rather utilizes a cascade of events that transduces the signal into a cellular change. ... A phosphorylated serine residue Phosphorylation is the addition of a phosphate (PO4) group to a protein or a small molecule or the introduction of a phosphate group into an organic molecule. ...


A very well understood example of extrinsic control is the regulation of glucose metabolism by the hormone insulin.[101] Insulin is produced in response to rises in blood glucose levels. Binding of the hormone to insulin receptors on cells then activates a cascade of protein kinases that cause the cells to take up glucose and convert it into storage molecules such as fatty acids and glycogen.[102] The metabolism of glycogen is controlled by activity of phosphorylase, the enzyme that breaks down glycogen, and glycogen synthase, the enzyme that makes it. These enzymes are regulated in a reciprocal fashion, with phosphorylation inhibiting glycogen synthase, but activating phosphorylase. Insulin causes glycogen synthesis by activating protein phosphatases and producing a decrease in the phosphorylation of these enzymes.[103] Insulin (from Latin insula, island, as it is produced in the Islets of Langerhans in the pancreas) is an anabolic polypeptide hormone that regulates carbohydrate metabolism. ... In medicine, blood sugar is a term used to refer to levels of glucose in the blood. ... In molecular biology, the insulin receptor is a transmembrane receptor that is activated by insulin. ... A protein kinase is an enzyme that modifies other proteins by chemically adding phosphate groups to them (phosphorylation). ... This article does not cite any references or sources. ... Phosphorylase is an enzyme that catalyzes the production of glucose phosphate from glycogen and inorganic phosphate. ... Glycogen synthase (UDP-glucose-glycogen glucosyltransferase) is a glycosyltransferase enzyme (EC number 2. ... A phosphatase is an enzyme that dephosphorylates its substrate; i. ...


Evolution

Further information: Molecular evolution and Phylogenetics
Evolutionary tree showing the common ancestry of organisms from all three domains of life. Bacteria are colored blue, eukaryotes red, and archaea green. Relative positions of some of the phyla included are shown around the tree.
Evolutionary tree showing the common ancestry of organisms from all three domains of life. Bacteria are colored blue, eukaryotes red, and archaea green. Relative positions of some of the phyla included are shown around the tree.

The central pathways of metabolism described above, such as glycolysis and the citric acid cycle, are present in all three domains of living things and were present in the last universal ancestor.[104][2] This universal ancestral cell was prokaryotic and probably a methanogen that had extensive amino acid, nucleotide, carbohydrate and lipid metabolism.[105][106] The retention of these ancient pathways during later evolution may be the result of these reactions being an optimal solution to their particular metabolic problems, with pathways such as glycolysis and the citric acid cycle producing their end products highly efficiently and in a minimal number of steps.[3][4] Molecular evolution is the process of the genetic material in populations of organisms changing over time. ... Phylogenetic groups, or taxa, can be monophyletic, paraphyletic, or polyphyletic. ... Image File history File links Size of this preview: 800 × 560 pixelsFull resolution (3384 × 2368 pixel, file size: 999 KB, MIME type: image/png) A highly resolved Tree Of Life, based on completely sequenced genomes [1]. The image was generated using iTOL: Interactive Tree Of Life[2], an online phylogenetic... Image File history File links Size of this preview: 800 × 560 pixelsFull resolution (3384 × 2368 pixel, file size: 999 KB, MIME type: image/png) A highly resolved Tree Of Life, based on completely sequenced genomes [1]. The image was generated using iTOL: Interactive Tree Of Life[2], an online phylogenetic... Fig. ... In biology, a domain (also superregnum, superkingdom, or empire) is the top-level grouping of organisms in scientific classification, higher than a kingdom. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota ARMAN The Archaea (), or archaebacteria, are a major group of microorganisms. ... In biological taxonomy, a phylum (Greek plural: phyla) is a taxon in the rank below kingdom and above class. ... The three-domain system is a biological classification introduced by Carl Woese in 1990 that emphasizes his separation of prokaryotes into two groups, originally called Eubacteria and Archaebacteria. ... Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend. ... Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... Methanogens are archaea that produce methane as a metabolic byproduct in anoxic conditions. ... This article is about evolution in biology. ...


Many models have been proposed to describe the mechanisms by which novel metabolic pathways evolve. These include the sequential addition of novel enzymes to a short ancestral pathway, the duplication and then divergence of entire pathways as well as the recruitment of pre-existing enzymes and their assembly into a novel reaction pathway.[107] The relative importance of these mechanisms is unclear, but genomic studies have shown that enzymes in a pathway are likely to have a shared ancestry, suggesting that many pathways have evolved in a step-by-step fashion with novel functions being created from pre-existing steps in the pathway.[108] Another possibility is that some parts of metabolism might exist as "modules" that can be reused in different pathways and perform similar functions on different molecules.[109]


The evolution of organisms can also produce the loss of metabolic pathways. For example, in some parasites metabolic processes that are not essential for survival are lost and preformed amino acids, nucleotides and carbohydrates may instead be scavenged from the host.[110] Similar reduced metabolic capabilities are seen in endosymbiotic organisms.[111] A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... An endosymbiont is any organism that lives within the body or cells of another organism, i. ...


Investigation and manipulation

Further information: Protein methods, proteomics, metabolomics and metabolic network modelling
Metabolic network of the Arabidopsis thaliana citric acid cycle. Enzymes and metabolites are shown as red squares and the interactions between them as black lines.
Metabolic network of the Arabidopsis thaliana citric acid cycle. Enzymes and metabolites are shown as red squares and the interactions between them as black lines.

Classically, metabolism is studied by a reductionist approach that focuses on a single metabolic pathway. Particularly valuable is the use of radioactive tracers at the whole-organism, tissue and cellular levels, which define the paths from precursors to final products by identifying radioactively-labelled intermediates and products.[112] The enzymes that catalyze these chemical reactions can then be purified and their kinetics and responses to inhibitors investigated. A parallel approach is to identify the small molecules in a cell or tissue; the complete set of these molecules is called the metabolome. Overall, these studies give a good view of the structure and function of simple metabolic pathways, but are inadequate when applied to more complex systems such as the metabolism of a complete cell.[113] Protein methods are the techniques used to study proteins. ... For the journal Proteomics, see Proteomics (journal). ... Metabolomics is the systematic study of the unique chemical fingerprints that specific cellular processes leave behind - specifically, the study of their small-molecule metabolite profiles. ... There are very few or no other articles that link to this one. ... Image File history File links Size of this preview: 568 × 599 pixel Image in higher resolution (836 × 882 pixel, file size: 62 KB, MIME type: image/png) Metabolic network showing the links between enzymes and metabolites that interact with the Arabidopsis TCA cycle KEGG classification M00009. ... Image File history File links Size of this preview: 568 × 599 pixel Image in higher resolution (836 × 882 pixel, file size: 62 KB, MIME type: image/png) Metabolic network showing the links between enzymes and metabolites that interact with the Arabidopsis TCA cycle KEGG classification M00009. ... With the sequencing of complete genomes, it is now possible to reconstruct the network of biochemical reactions in many organisms, from bacteria to human. ... Binomial name Arabidopsis thaliana (L.) Heynh. ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Metabolomics is the systematic study of the unique chemical fingerprints that specific cellular processes leave behind - specifically, the study of their small-molecule metabolite profiles. ... Descartes held that non-human animals could be reductively explained as automata — De homines 1622. ... A radioactive tracer is a substance containing a radioactive isotope (radioisotope). ... Protein purification is the process of isolating proteins from a homogenate, which may comprise cell and tissue components, including DNA, cell membrane and other proteins. ... Dihydrofolate reductase from with its two substrates, dihydrofolate (right) and NADPH (left), bound in the active site. ... HIV protease in a complex with the protease inhibitor ritonavir. ... Metabolome is the whole set of metabolic entities and small pathway motifs in a cell, tissue, organ, organisms, and species. ...


An idea of the complexity of the metabolic networks in cells that contain thousands of different enzymes is given by the figure showing the interactions between just 43 proteins and 40 metabolites to the right: the sequences of genomes provide lists containing anything up to 45,000 genes.[114] However, it is now possible to use this genomic data to reconstruct complete networks of biochemical reactions and produce more holistic mathematical models that may explain and predict their behavior.[115] These models are especially powerful when used to integrate the pathway and metabolite data obtained through classical methods with data on gene expression from proteomic and DNA microarray studies.[116] With the sequencing of complete genomes, it is now possible to reconstruct the network of biochemical reactions in many organisms, from bacteria to human. ... Whole redirects here. ... Gene expression, or simply expression, is the process by which the inheritable information which comprises a gene, such as the DNA sequence, is made manifest as a physical and biologically functional gene product, such as protein or RNA. Several steps in the gene expression process may be modulated, including the... For the journal Proteomics, see Proteomics (journal). ... It has been suggested that Gene chip technology be merged into this article or section. ...


A major technological application of this information is metabolic engineering. Here, organisms such as yeast, plants or bacteria are genetically-modified to make them more useful in biotechnology and aid the production of drugs such as antibiotics or industrial chemicals such as 1,3-propanediol and shikimic acid.[117] These genetic modifications usually aim to reduce the amount of energy used to produce the product, increase yields and reduce the production of wastes.[118] Cellular metabolism can be optimized for industrial use. ... Typical divisions Ascomycota (sac fungi) Saccharomycotina (true yeasts) Taphrinomycotina Schizosaccharomycetes (fission yeasts) Basidiomycota (club fungi) Urediniomycetes Sporidiales Yeasts are a growth form of eukaryotic microorganisms classified in the kingdom Fungi, with approximately 1,500 species described. ... For other uses, see Plant (disambiguation). ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... The structure of insulin Biotechnology is technology based on biology, especially when used in agriculture, food science, and medicine. ... For other meanings, see Drug (disambiguation). ... Staphylococcus aureus - Antibiotics test plate. ... 1,3-Propanediol, also propane-1,3-diol or trimethylene glycol, is a three-carbon diol. ... Shikimic acid, more commonly known as its anionic form shikimate, is an important biochemical intermediate in plants and microorganisms. ...


History

Further information: History of biochemistry and History of molecular biology
Santorio Santorio in his steelyard balance, from Ars de statica medecina, first published 1614
Santorio Santorio in his steelyard balance, from Ars de statica medecina, first published 1614

The term metabolism is derived from the Greek Μεταβολισμός – "Metabolismos" for "change", or "overthrow".[119] The history of the scientific study of metabolism spans 400 years and has moved from examining whole animals in early studies, to examining individual metabolic reactions in modern biochemistry. The first controlled experiments in human metabolism were published by Santorio Santorio in 1614 in his book Ars de statica medecina.[120] He described how he weighed himself before and after eating, sleeping, working, sex, fasting, drinking, and excreting. He found that most of the food he took in was lost through what he called "insensible perspiration". The history of biochemistry spans approximately 400 years. ... The history of molecular biology begins in the 1930s with the convergence of various, previously distinct biological disciplines: biochemistry, genetics, microbiology, and virology. ... Image File history File links Santorio Santorio weighed himself before and after a meal, conducting the first controlled test of metabolism, and published the results in Ars (lol you said ars) de statica medecina, 1614 17th century book illustration File history Legend: (cur) = this is the current file, (del) = delete... Image File history File links Santorio Santorio weighed himself before and after a meal, conducting the first controlled test of metabolism, and published the results in Ars (lol you said ars) de statica medecina, 1614 17th century book illustration File history Legend: (cur) = this is the current file, (del) = delete... Engraving of Sanctorius of Padua Santorio Santorio (1561–1636), also called Santorio Santorii, Sanctorius of Padua, and various combinations of these names, was an Italian physiologist, physician, and professor. ... Engraving of Sanctorius of Padua Santorio Santorio (1561–1636), also called Santorio Santorii, Sanctorius of Padua, and various combinations of these names, was an Italian physiologist, physician, and professor. ... Events April 5 - In Virginia, Native American Pocahontas marries English colonist John Rolfe. ...


In these early studies, the mechanisms of these metabolic processes had not been identified and a vital force was thought to animate living tissue.[121] In the 19th century, when studying the fermentation of sugar to alcohol by yeast, Louis Pasteur concluded that fermentation was catalyzed by substances within the yeast cells he called "ferments". He wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells."[122] This discovery, along with the publication by Friedrich Wöhler in 1828 of the chemical synthesis of urea,[123] proved that the organic compounds and chemical reactions found in cells were no different in principle than any other part of chemistry. Vitalism is the doctrine that vital forces are active in living organisms, so that life cannot be explained solely by mechanism. ... For other uses, see Fermentation. ... This article does not cite any references or sources. ... Typical divisions Ascomycota (sac fungi) Saccharomycotina (true yeasts) Taphrinomycotina Schizosaccharomycetes (fission yeasts) Basidiomycota (club fungi) Urediniomycetes Sporidiales Yeasts are a growth form of eukaryotic microorganisms classified in the kingdom Fungi, with approximately 1,500 species described. ... Louis Pasteur (December 27, 1822 – September 28, 1895) was a French chemist best known for his remarkable breakthroughs in microbiology. ... Friedrich Wöhler Friedrich Wöhler (July 31, 1800 - September 23, 1882) was a German chemist, best-known for his synthesis of urea, but also the first to isolate several of the elements. ... Year 1828 (MDCCCXXVIII) was a leap year starting on Tuesday (link will display the full calendar) of the Gregorian Calendar (or a leap year starting on Thursday of the 12-day slower Julian calendar). ... Urea is an organic compound with the chemical formula (NH2)2CO. Urea is also known as carbamide, especially in the recommended International Nonproprietary Names (rINN) in use in Europe. ...


It was the discovery of enzymes at the beginning of the 20th century by Eduard Buchner that separated the study of the chemical reactions of metabolism from the biological study of cells, and marked the beginnings of biochemistry.[124] The mass of biochemical knowledge grew rapidly throughout the early 20th century. One of the most prolific of these modern biochemists was Hans Krebs who made huge contributions to the study of metabolism.[125] He discovered the urea cycle and later, working with Hans Kornberg, the citric acid cycle and the glyoxylate cycle.[126][62] Modern biochemical research has been greatly aided by the development of new techniques such as chromatography, X-ray diffraction, NMR spectroscopy, radioisotopic labelling, electron microscopy and molecular dynamics simulations. These techniques have allowed the discovery and detailed analysis of the many molecules and metabolic pathways in cells. Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Eduard Buchner (May 20, 1860 -- August 12, 1917) was a German chemist and zymologist, the winner of the 1907 Nobel Prize in Chemistry for his work on fermentation. ... Biochemistry is the study of the chemical processes in living organisms. ... Sir Hans Adolf Krebs (August 25, 1900 – November 22, 1981) was a German, later British medical doctor and biochemist. ... Sir Hans Kornberg (born 14 January 1928) is a British biologist and a Fellow of the Royal Society. ... For the Second Person album, see Chromatography (album). ... X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of x-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ... Pacific Northwest National Laboratorys high magnetic field (800 MHz) NMR spectrometer being loaded with a sample. ... Radioisotopic labeling is a technique for tracking the passage of a sample of substance through a system. ... An electron microscope is a type of microscope that uses electrons to illuminate and create an image of a specimen. ... Molecular dynamics (MD) is a form of computer simulation wherein atoms and molecules are allowed to interact for a period of time under known laws of physics, giving a view of the motion of the atoms. ...


See also

Wikibooks
Wikibooks has more on the topic of
Metabolism
Wikiversity
At Wikiversity, you can learn about:
Metabolism Portal

Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a wiki for the creation of books. ... Image File history File links This is a lossless scalable vector image. ... Wikiversity logo Wikiversity is a Wikimedia Foundation beta project[1], devoted to learning materials and activities, located at www. ... Image File history File links Portal. ... Inborn errors of metabolism comprise a large class of genetic diseases involving disorders of metabolism. ... Basal metabolic rate (BMR) is the amount of energy expended while at rest in a neutrally temperate environment, in the post-absorptive state (meaning that the digestive system is inactive, which requires about twelve hours of fasting in humans). ... Thermic effect of food (also commonly known simply as thermic effect when the context is known), or TEF in shorthand, is the increment in energy expenditure above resting metabolic rate due to the cost of processing food for storage and use. ... The iron-sulfur world theory is a hypothesis for the origin of life advanced by Günter Wächtershäuser, a Munich chemist and patent lawyer, involving forms of iron and sulfur. ... This article does not adequately cite its references or sources. ... The world’s first ice-calorimeter, used in the winter of 1782-83, by Antoine Lavoisier and Pierre-Simon Laplace, to determine the heat evolved in various chemical changes; calculations which were based on Joseph Black’s prior discovery of latent heat. ... Respirometry is a general term that encompass a number of powerful techniques for obtaining estimates of the rates of metabolism of vertebrates, invertebrates, plants, tissues, cells, or microorganisms via an indirect measure of heat production (calorimetry). ... There are very few or no other articles that link to this one. ...

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Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 67th day of the year (68th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 51st day of the year in the Gregorian calendar. ...

Further reading

Introductory

  • Rose, S. and Mileusnic, R., The Chemistry of Life. (Penguin Press Science, 1999), ISBN 0-14027-273-9
  • Schneider, E. D. and Sagan, D., Into the Cool: Energy Flow, Thermodynamics, and Life. (University Of Chicago Press, 2005), ISBN 0-22673-936-8
  • Lane, N., Oxygen: The Molecule that Made the World. (Oxford University Press, USA, 2004), ISBN 0-19860-783-0

Advanced

  • Price, N. and Stevens, L., Fundamentals of Enzymology: Cell and Molecular Biology of Catalytic Proteins. (Oxford University Press, 1999), ISBN 0-19850-229-X
  • Berg, J. Tymoczko, J. and Stryer, L., Biochemistry. (W. H. Freeman and Company, 2002), ISBN 0-71674-955-6
  • Cox, M. and Nelson, D. L., Lehninger Principles of Biochemistry. (Palgrave Macmillan, 2004), ISBN 0-71674-339-6
  • Brock, T. D. Madigan, M. T. Martinko, J. and Parker J., Brock's Biology of Microorganisms. (Benjamin Cummings, 2002), ISBN 0-13066-271-2
  • Da Silva, J.J.R.F. and Williams, R. J. P., The Biological Chemistry of the Elements: The Inorganic Chemistry of Life. (Clarendon Press, 1991), ISBN 0-19855-598-9
  • Nicholls, D. G. and Ferguson, S. J., Bioenergetics. (Academic Press Inc., 2002), ISBN 0-12518-121-3

External links

Protein metabolism denotes the various biochemical processes responsible for the synthesis of proteins and amino acids, and the breakdown of proteins (catabolism). ... The smooth endoplasmic reticulum is responsible for some carbohydrate metabolism. ... This article or section is in need of attention from an expert on the subject. ... Human beings use 20 mg of iron each day for the production of new red blood cells, much of which is recycled from old red blood cells. ...

Major families of biochemicals
Peptides | Amino acids | Nucleic acids | Carbohydrates | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides
Analogues of nucleic acids:   Analogues of nucleic acids:

  Results from FactBites:
 
Bodybuilding.com - Jesse Cannone - Take Control Of Your Metabolism: Quick Tips For Increased Muscle Tone, Faster Fat ... (1377 words)
So many people are talking about how slow their metabolism is and why they need to start taking the latest diet supplement scam yet they don't even understand how the human metabolism works.
o many people are talking about how slow their metabolism is and why they need to start taking the latest diet supplement scam yet they don't even understand how the human metabolism works.
metabolism is the rate at which your body burns calories to sustain life
Metabolism & Metabolic Syndrome (3239 words)
While cardiologists and diabetologists argue about definitions and criteria of the metabolic syndrome, the events are taking their own course: though the statistics remains frightening, these very criteria are already working toward practical recommendations on how to prevent and fight this “epidemic of the 21th century.
The metabolic abnormalities associated with insulin resistance have been shown to be sixfold higher in smokers than in non-smokers.
If, plus to metabolic syndrome, they had a tendency to inflammation, their odds were 66 percent, while people with the syndrome but no inflammation did not show an increased likelihood of mental health impairment at all.
  More results at FactBites »

 
 

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