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64-405: 4,4′-Dichlorodiphenyl sulfone ( DCDPS ) is an organic compound with the formula (ClC 6 H 4 ) 2 SO 2 . Classified as a sulfone , this white solid is most commonly used as a precursor to polymers that are rigid and temperature-resistant such as PES or Udel. DCDPS is synthesized via sulfonation of chlorobenzene with sulfuric acid , often in the presence of various additives to optimize

128-509: A bilayer structure of phospholipids. The phospholipid molecule is amphipathic ; it contains a hydrophilic polar head and a hydrophobic nonpolar tail. The phospholipid heads interact with each other and aqueous media, while the hydrocarbon tails orient themselves in the center, away from water. These latter interactions drive the bilayer structure that acts as a barrier for ions and molecules. There are various types of phospholipids; consequently, their synthesis pathways differ. However,

192-469: A primer with a free 3'OH in which to incorporate nucleotides. In order for DNA replication to occur, a replication fork is created by enzymes called helicases which unwind the DNA helix. Topoisomerases at the replication fork remove supercoils caused by DNA unwinding, and single-stranded DNA binding proteins maintain the two single-stranded DNA templates stabilized prior to replication. DNA synthesis

256-454: A purine or pyrimidine base with a glycosidic bond and a phosphate group at the 5' location of the sugar. The DNA nucleotides adenosine and guanosine consist of a purine base attached to a ribose sugar with a glycosidic bond. In the case of RNA nucleotides deoxyadenosine and deoxyguanosine , the purine bases are attached to a deoxyribose sugar with a glycosidic bond. The purine bases on DNA and RNA nucleotides are synthesized in

320-446: A charged tRNA that is ready to add amino acids to the growing polypeptide chain. In addition to binding an amino acid, tRNA has a three nucleotide unit called an anticodon that base pairs with specific nucleotide triplets on the mRNA called codons ; codons encode a specific amino acid. This interaction is possible thanks to the ribosome, which serves as the site for protein synthesis. The ribosome possesses three tRNA binding sites:

384-450: A class of molecules called sterols . Sterols have four fused rings and a hydroxyl group . Cholesterol is a particularly important molecule. Not only does it serve as a component of lipid membranes, it is also a precursor to several steroid hormones, including cortisol , testosterone , and estrogen . Cholesterol is synthesized from acetyl CoA . The pathway is shown below: More generally, this synthesis occurs in three stages, with

448-402: A hydrocarbon chain "tail". These fatty acids create larger components, which in turn incorporate noncovalent interactions to form the lipid bilayer. Fatty acid chains are found in two major components of membrane lipids: phospholipids and sphingolipids . A third major membrane component, cholesterol , does not contain these fatty acid units. The foundation of all biomembranes consists of

512-458: A polar head and nonpolar tails. Unlike phospholipids, sphingolipids have a sphingosine backbone. Sphingolipids exist in eukaryotic cells and are particularly abundant in the central nervous system . For example, sphingomyelin is part of the myelin sheath of nerve fibers. Sphingolipids are formed from ceramides that consist of a fatty acid chain attached to the amino group of a sphingosine backbone. These ceramides are synthesized from

576-629: A process called translation . During translation, genetic material called mRNA is read by ribosomes to generate a protein polypeptide chain. This process requires transfer RNA (tRNA) which serves as an adaptor by binding amino acids on one end and interacting with mRNA at the other end; the latter pairing between the tRNA and mRNA ensures that the correct amino acid is added to the chain. Protein synthesis occurs in three phases: initiation, elongation, and termination. Prokaryotic ( archaeal and bacterial ) translation differs from eukaryotic translation ; however, this section will mostly focus on

640-474: A regulative force must exist within living bodies. Berzelius also contended that compounds could be distinguished by whether they required any organisms in their synthesis (organic compounds) or whether they did not ( inorganic compounds ). Vitalism taught that formation of these "organic" compounds were fundamentally different from the "inorganic" compounds that could be obtained from the elements by chemical manipulations in laboratories. Vitalism survived for

704-452: A short period after the formulation of modern ideas about the atomic theory and chemical elements . It first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid , a compound known to occur only in living organisms, from cyanogen . A further experiment was Wöhler's 1828 synthesis of urea from the inorganic salts potassium cyanate and ammonium sulfate . Urea had long been considered an "organic" compound, as it

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768-445: A single cellular organelle (e.g., mitochondrial fatty acid synthesis pathways), while others involve enzymes that are located across an array of cellular organelles and structures (e.g., the biosynthesis of glycosylated cell surface proteins). Elements of biosynthesis include: precursor compounds, chemical energy (e.g. ATP ), and catalytic enzymes which may need coenzymes (e.g. NADH , NADPH ). These elements create monomers ,

832-404: A single element and so not generally considered chemical compounds . The word "organic" in this context does not mean "natural". Vitalism was a widespread conception that substances found in organic nature are formed from the chemical elements by the action of a "vital force" or "life-force" ( vis vitalis ) that only living organisms possess. In the 1810s, Jöns Jacob Berzelius argued that

896-634: A small percentage of Earth's crust , they are of central importance because all known life is based on organic compounds. Living things incorporate inorganic carbon compounds into organic compounds through a network of processes ( the carbon cycle ) that begins with the conversion of carbon dioxide and a hydrogen source like water into simple sugars and other organic molecules by autotrophic organisms using light ( photosynthesis ) or other sources of energy. Most synthetically-produced organic compounds are ultimately derived from petrochemicals consisting mainly of hydrocarbons , which are themselves formed from

960-421: A transition metal and to oxygen, and are often prepared directly from metal and carbon monoxide . Nickel tetracarbonyl is typically classified as an organometallic compound as it satisfies the broad definition that organometallic chemistry covers all compounds that contain at least one carbon to metal covalent bond; it is unknown whether organometallic compounds form a subset of organic compounds. For example,

1024-493: A twelve-step reaction mechanism present in most single-celled organisms. Higher eukaryotes employ a similar reaction mechanism in ten reaction steps. Purine bases are synthesized by converting phosphoribosyl pyrophosphate (PRPP) to inosine monophosphate (IMP), which is the first key intermediate in purine base biosynthesis. Further enzymatic modification of IMP produces the adenosine and guanosine bases of nucleotides. Other DNA and RNA nucleotide bases that are linked to

1088-1692: A variety of ways. One major distinction is between natural and synthetic compounds. Organic compounds can also be classified or subdivided by the presence of heteroatoms , e.g., organometallic compounds , which feature bonds between carbon and a metal , and organophosphorus compounds , which feature bonds between carbon and a phosphorus . Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers . Natural compounds refer to those that are produced by plants or animals. Many of these are still extracted from natural sources because they would be more expensive to produce artificially. Examples include most sugars , some alkaloids and terpenoids , certain nutrients such as vitamin B 12 , and, in general, those natural products with large or stereoisometrically complicated molecules present in reasonable concentrations in living organisms. Further compounds of prime importance in biochemistry are antigens , carbohydrates , enzymes , hormones , lipids and fatty acids , neurotransmitters , nucleic acids , proteins , peptides and amino acids , lectins , vitamins , and fats and oils . Compounds that are prepared by reaction of other compounds are known as " synthetic ". They may be either compounds that are already found in plants/animals or those artificial compounds that do not occur naturally . Most polymers (a category that includes all plastics and rubbers ) are organic synthetic or semi-synthetic compounds. Many organic compounds—two examples are ethanol and insulin —are manufactured industrially using organisms such as bacteria and yeast. Typically,

1152-434: Is a term most often referring to multi-step, enzyme - catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthesis) serve as enzyme substrates , with conversion by the living organism either into simpler or more complex products . Examples of biosynthetic pathways include those for the production of amino acids , lipid membrane components, and nucleotides , but also for

1216-411: Is a two-step reaction which involves the conversion of UMP to UTP . Phosphate addition to UMP is catalyzed by a kinase enzyme. The enzyme CTP synthase catalyzes the next reaction step: the conversion of UTP to CTP by transferring an amino group from glutamine to uridine; this forms the cytosine base of CTP. The mechanism, which depicts the reaction UTP + ATP + glutamine ⇔ CTP + ADP + glutamate,

1280-972: Is any compound that contains a significant amount of carbon—even though many of the organic compounds known today have no connection to any substance found in living organisms. The term carbogenic has been proposed by E. J. Corey as a modern alternative to organic , but this neologism remains relatively obscure. The organic compound L -isoleucine molecule presents some features typical of organic compounds: carbon–carbon bonds , carbon–hydrogen bonds , as well as covalent bonds from carbon to oxygen and to nitrogen. As described in detail below, any definition of organic compound that uses simple, broadly-applicable criteria turns out to be unsatisfactory, to varying degrees. The modern, commonly accepted definition of organic compound essentially amounts to any carbon-containing compound, excluding several classes of substances traditionally considered "inorganic". The list of substances so excluded varies from author to author. Still, it

1344-447: Is below: Cytosine is a nucleotide that is present in both DNA and RNA. However, uracil is only found in RNA. Therefore, after UTP is synthesized, it is must be converted into a deoxy form to be incorporated into DNA. This conversion involves the enzyme ribonucleoside triphosphate reductase . This reaction that removes the 2'-OH of the ribose sugar to generate deoxyribose is not affected by

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1408-442: Is catalyzed by the enzyme phosphoserine phosphatase , which dephosphorylates L-phosphoserine to yield L-serine . There are two known pathways for the biosynthesis of glycine. Organisms that use ethanol and acetate as the major carbon source utilize the glyconeogenic pathway to synthesize glycine . The other pathway of glycine biosynthesis is known as the glycolytic pathway. This pathway converts serine synthesized from

1472-403: Is catalyzed by the enzyme pyrroline-5-carboxylate synthase (P5CS), which catalyzes the reduction of the ϒ-carboxyl group of L-glutamate 5-phosphate. This results in the formation of glutamate semialdehyde, which spontaneously cyclizes to pyrroline-5-carboxylate. Pyrroline-5-carboxylate is further reduced by the enzyme pyrroline-5-carboxylate reductase (P5CR) to yield a proline amino acid. In

1536-410: Is composed of nucleotides that are joined by phosphodiester bonds . DNA synthesis , which takes place in the nucleus , is a semiconservative process, which means that the resulting DNA molecule contains an original strand from the parent structure and a new strand. DNA synthesis is catalyzed by a family of DNA polymerases that require four deoxynucleoside triphosphates, a template strand , and

1600-412: Is converted to phosphatidate via the addition of another fatty acid chain contributed by a second acyl CoA; all of these steps are catalyzed by the glycerol phosphate acyltransferase enzyme. Phospholipid synthesis continues in the endoplasmic reticulum, and the biosynthesis pathway diverges depending on the components of the particular phospholipid. Like phospholipids, these fatty acid derivatives have

1664-710: Is generally agreed upon that there are (at least) a few carbon-containing compounds that should not be considered organic. For instance, almost all authorities would require the exclusion of alloys that contain carbon, including steel (which contains cementite , Fe 3 C ), as well as other metal and semimetal carbides (including "ionic" carbides, e.g, Al 4 C 3 and CaC 2 and "covalent" carbides, e.g. B 4 C and SiC , and graphite intercalation compounds, e.g. KC 8 ). Other compounds and materials that are considered 'inorganic' by most authorities include: metal carbonates , simple oxides of carbon ( CO , CO 2 , and arguably, C 3 O 2 ),

1728-446: Is initiated by the RNA polymerase primase , which makes an RNA primer with a free 3'OH. This primer is attached to the single-stranded DNA template, and DNA polymerase elongates the chain by incorporating nucleotides; DNA polymerase also proofreads the newly synthesized DNA strand. During the polymerization reaction catalyzed by DNA polymerase, a nucleophilic attack occurs by the 3'OH of

1792-547: Is made discontinuously in Okazaki fragments and grows away from the replication fork. Okazaki fragments are covalently joined by DNA ligase to form a continuous strand. Then, to complete DNA replication, RNA primers are removed, and the resulting gaps are replaced with DNA and joined via DNA ligase. A protein is a polymer that is composed from amino acids that are linked by peptide bonds . There are more than 300 amino acids found in nature of which only twenty two, known as

1856-479: Is on a carbon atom. For historical reasons discussed below, a few types of carbon-containing compounds, such as carbides , carbonates (excluding carbonate esters ), simple oxides of carbon (for example, CO and CO 2 ) and cyanides are generally considered inorganic compounds . Different forms ( allotropes ) of pure carbon, such as diamond , graphite , fullerenes and carbon nanotubes are also excluded because they are simple substances composed of

1920-469: Is responsible for synthesizing thymine residues from dUMP to dTMP . This reaction transfers a methyl group onto the uracil base of dUMP to generate dTMP. The thymidylate synthase reaction, dUMP + 5,10-methylenetetrahydrofolate ⇔ dTMP + dihydrofolate, is shown to the right. Although there are differences between eukaryotic and prokaryotic DNA synthesis, the following section denotes key characteristics of DNA replication shared by both organisms. DNA

1984-431: Is synthesized by an ATP-dependent addition of an amino group onto aspartate; asparagine synthetase catalyzes the addition of nitrogen from glutamine or soluble ammonia to aspartate to yield asparagine. The diaminopimelic acid biosynthetic pathway of lysine belongs to the aspartate family of amino acids. This pathway involves nine enzyme-catalyzed reactions that convert aspartate to lysine. Protein synthesis occurs via

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2048-582: The DNA of an organism is altered to express compounds not ordinarily produced by the organism. Many such biotechnology -engineered compounds did not previously exist in nature. A great number of more specialized databases exist for diverse branches of organic chemistry. The main tools are proton and carbon-13 NMR spectroscopy , IR Spectroscopy , Mass spectrometry , UV/Vis Spectroscopy and X-ray crystallography . Biosynthesis Biosynthesis , i.e., chemical synthesis occurring in biological contexts,

2112-420: The acylation of sphingosine. The biosynthetic pathway for sphingosine is found below: As the image denotes, during sphingosine synthesis, palmitoyl CoA and serine undergo a condensation reaction which results in the formation of 3-dehydrosphinganine. This product is then reduced to form dihydrospingosine, which is converted to sphingosine via the oxidation reaction by FAD . This lipid belongs to

2176-781: The allotropes of carbon, cyanide derivatives not containing an organic residue (e.g., KCN , (CN) 2 , BrCN , cyanate anion OCN , etc.), and heavier analogs thereof (e.g., cyaphide anion CP , CSe 2 , COS ; although carbon disulfide CS 2 is often classed as an organic solvent). Halides of carbon without hydrogen (e.g., CF 4 and CClF 3 ), phosgene ( COCl 2 ), carboranes , metal carbonyls (e.g., nickel tetracarbonyl ), mellitic anhydride ( C 12 O 9 ), and other exotic oxocarbons are also considered inorganic by some authorities. Nickel tetracarbonyl ( Ni(CO) 4 ) and other metal carbonyls are often volatile liquids, like many organic compounds, yet they contain only carbon bonded to

2240-519: The proteinogenic amino acids , are the building blocks for protein. Only green plants and most microbes are able to synthesize all of the 20 standard amino acids that are needed by all living species. Mammals can only synthesize ten of the twenty standard amino acids. The other amino acids, valine , methionine , leucine , isoleucine , phenylalanine , lysine , threonine and tryptophan for adults and histidine , and arginine for babies are obtained through diet. The general structure of

2304-473: The N-acetyl-L-ornithine. The acetyl group of acetylornithine is removed by the enzyme acetylornithinase (AO) or ornithine acetyltransferase (OAT), and this yields ornithine . Then, the enzymes citrulline and argininosuccinate convert ornithine to arginine. There are two distinct lysine biosynthetic pathways: the diaminopimelic acid pathway and the α-aminoadipate pathway . The most common of

2368-414: The amino acid lysine , which is derived from α-ketoglutarate . The biosynthesis of glutamate and glutamine is a key step in the nitrogen assimilation discussed above. The enzymes GOGAT and GDH catalyze the nitrogen assimilation reactions. In bacteria, the enzyme glutamate 5-kinase initiates the biosynthesis of proline by transferring a phosphate group from ATP onto glutamate. The next reaction

2432-499: The aspartate family even though part of their carbon skeleton is derived from pyruvate . In the case of methionine, the methyl carbon is derived from serine and the sulfur group, but in most organisms, it is derived from cysteine. The biosynthesis of aspartate is a one step reaction that is catalyzed by a single enzyme. The enzyme aspartate aminotransferase catalyzes the transfer of an amino group from aspartate onto α-ketoglutarate to yield glutamate and oxaloacetate . Asparagine

2496-455: The bases attached to the sugar. This non-specificity allows ribonucleoside triphosphate reductase to convert all nucleotide triphosphates to deoxyribonucleotide by a similar mechanism. In contrast to uracil, thymine bases are found mostly in DNA, not RNA. Cells do not normally contain thymine bases that are linked to ribose sugars in RNA, thus indicating that cells only synthesize deoxyribose-linked thymine. The enzyme thymidylate synthetase

2560-403: The building blocks for macromolecules. Some important biological macromolecules include: proteins , which are composed of amino acid monomers joined via peptide bonds , and DNA molecules, which are composed of nucleotides joined via phosphodiester bonds . Biosynthesis occurs due to a series of chemical reactions. For these reactions to take place, the following elements are necessary: In

2624-461: The carbons needed for the biosynthesis of the methionine and histidine . During serine biosynthesis, the enzyme phosphoglycerate dehydrogenase catalyzes the initial reaction that oxidizes 3-phospho-D-glycerate to yield 3-phosphonooxypyruvate . The following reaction is catalyzed by the enzyme phosphoserine aminotransferase , which transfers an amino group from glutamate onto 3-phosphonooxypyruvate to yield L-phosphoserine . The final step

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2688-408: The commonalities between the two organisms. Before translation can begin, the process of binding a specific amino acid to its corresponding tRNA must occur. This reaction, called tRNA charging, is catalyzed by aminoacyl tRNA synthetase . A specific tRNA synthetase is responsible for recognizing and charging a particular amino acid. Furthermore, this enzyme has special discriminator regions to ensure

2752-411: The correct binding between tRNA and its cognate amino acid. The first step for joining an amino acid to its corresponding tRNA is the formation of aminoacyl-AMP: This is followed by the transfer of the aminoacyl group from aminoacyl-AMP to a tRNA molecule. The resulting molecule is aminoacyl-tRNA : The combination of these two steps, both of which are catalyzed by aminoacyl tRNA synthetase, produces

2816-576: The discipline known as organic chemistry . For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts ), along with a few other exceptions (e.g., carbon dioxide , and even hydrogen cyanide despite the fact it contains a carbon-hydrogen bond), are generally considered inorganic . Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only

2880-474: The enzyme glutamate dehydrogenase (GDH). GDH is able to transfer ammonia onto 2-oxoglutarate and form glutamate. Furthermore, the enzyme glutamine synthetase (GS) is able to transfer ammonia onto glutamate and synthesize glutamine, replenishing glutamine. The glutamate family of amino acids includes the amino acids that derive from the amino acid glutamate. This family includes: glutamate, glutamine , proline , and arginine . This family also includes

2944-409: The enzyme glutamine oxoglutarate aminotransferase (GOGAT) which removes the amide amino group of glutamine and transfers it onto 2-oxoglutarate , producing two glutamate molecules. In this catalysis reaction, glutamine serves as the nitrogen source. An image illustrating this reaction is found to the right. The other pathway for incorporating nitrogen onto the α-carbon of amino acids involves

3008-468: The enzyme serine acetyltransferase catalyzes the transfer of acetyl group from acetyl-CoA onto L-serine to yield O-acetyl-L-serine . The following reaction step, catalyzed by the enzyme O-acetyl serine (thiol) lyase , replaces the acetyl group of O-acetyl-L-serine with sulfide to yield cysteine. The aspartate family of amino acids includes: threonine , lysine , methionine , isoleucine , and aspartate. Lysine and isoleucine are considered part of

3072-938: The evidence of covalent Fe-C bonding in cementite , a major component of steel, places it within this broad definition of organometallic, yet steel and other carbon-containing alloys are seldom regarded as organic compounds. Thus, it is unclear whether the definition of organometallic should be narrowed, whether these considerations imply that organometallic compounds are not necessarily organic, or both. Metal complexes with organic ligands but no carbon-metal bonds (e.g., (CH 3 CO 2 ) 2 Cu ) are not considered organometallic; instead, they are called metal-organic compounds (and might be considered organic). The relatively narrow definition of organic compounds as those containing C-H bonds excludes compounds that are (historically and practically) considered organic. Neither urea CO(NH 2 ) 2 nor oxalic acid (COOH) 2 are organic by this definition, yet they were two key compounds in

3136-475: The first stage taking place in the cytoplasm and the second and third stages occurring in the endoplasmic reticulum. The stages are as follows: The biosynthesis of nucleotides involves enzyme- catalyzed reactions that convert substrates into more complex products. Nucleotides are the building blocks of DNA and RNA . Nucleotides are composed of a five-membered ring formed from ribose sugar in RNA, and deoxyribose sugar in DNA; these sugars are linked to

3200-409: The first step in phospholipid synthesis involves the formation of phosphatidate or diacylglycerol 3-phosphate at the endoplasmic reticulum and outer mitochondrial membrane . The synthesis pathway is found below: The pathway starts with glycerol 3-phosphate, which gets converted to lysophosphatidate via the addition of a fatty acid chain provided by acyl coenzyme A . Then, lysophosphatidate

3264-552: The first step of arginine biosynthesis in bacteria, glutamate is acetylated by transferring the acetyl group from acetyl-CoA at the N-α position; this prevents spontaneous cyclization. The enzyme N-acetylglutamate synthase (glutamate N-acetyltransferase) is responsible for catalyzing the acetylation step. Subsequent steps are catalyzed by the enzymes N-acetylglutamate kinase , N-acetyl-gamma-glutamyl-phosphate reductase , and acetylornithine/succinyldiamino pimelate aminotransferase and yield

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3328-443: The formation of the 4,4′-isomer: It can also be produced by chlorination of diphenylsulfone . With chloride substituents activated toward substitution, DCDPS is useful in the production of polysulfones : Organic compound Due to carbon's ability to catenate (form chains with other carbon atoms ), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise

3392-400: The growing chain on the innermost phosphorus atom of a deoxynucleoside triphosphate; this yields the formation of a phosphodiester bridge that attaches a new nucleotide and releases pyrophosphate . Two types of strands are created simultaneously during replication: the leading strand , which is synthesized continuously and grows towards the replication fork, and the lagging strand , which

3456-404: The high pressure and temperature degradation of organic matter underground over geological timescales. This ultimate derivation notwithstanding, organic compounds are no longer defined as compounds originating in living things, as they were historically. In chemical nomenclature, an organyl group , frequently represented by the letter R, refers to any monovalent substituent whose open valence

3520-419: The intermediates of glycolysis to glycine. In the glycolytic pathway, the enzyme serine hydroxymethyltransferase catalyzes the cleavage of serine to yield glycine and transfers the cleaved carbon group of serine onto tetrahydrofolate , forming 5,10-methylene-tetrahydrofolate . Cysteine biosynthesis is a two-step reaction that involves the incorporation of inorganic sulfur . In microorganisms and plants,

3584-601: The mineral mellite ( Al 2 C 6 (COO) 6 ·16H 2 O ). A slightly broader definition of the organic compound includes all compounds bearing C-H or C-C bonds. This would still exclude urea. Moreover, this definition still leads to somewhat arbitrary divisions in sets of carbon-halogen compounds. For example, CF 4 and CCl 4 would be considered by this rule to be "inorganic", whereas CHF 3 , CHCl 3 , and C 2 Cl 6 would be organic, though these compounds share many physical and chemical properties. Organic compounds may be classified in

3648-623: The production of all classes of biological macromolecules , and of acetyl-coenzyme A , adenosine triphosphate , nicotinamide adenine dinucleotide and other key intermediate and transactional molecules needed for metabolism . Thus, in biosynthesis, any of an array of compounds , from simple to complex, are converted into other compounds, and so it includes both the catabolism and anabolism (building up and breaking down) of complex molecules (including macromolecules ). Biosynthetic processes are often represented via charts of metabolic pathways . A particular biosynthetic pathway may be located within

3712-456: The ribose sugar via a glycosidic bond are thymine , cytosine and uracil (which is only found in RNA). Uridine monophosphate biosynthesis involves an enzyme that is located in the mitochondrial inner membrane and multifunctional enzymes that are located in the cytosol . After the uridine nucleotide base is synthesized, the other bases, cytosine and thymine are synthesized. Cytosine biosynthesis

3776-426: The simplest sense, the reactions that occur in biosynthesis have the following format: Some variations of this basic equation which will be discussed later in more detail are: Many intricate macromolecules are synthesized in a pattern of simple, repeated structures. For example, the simplest structures of lipids are fatty acids . Fatty acids are hydrocarbon derivatives; they contain a carboxyl group "head" and

3840-419: The standard amino acids includes a primary amino group , a carboxyl group and the functional group attached to the α-carbon . The different amino acids are identified by the functional group. As a result of the three different groups attached to the α-carbon, amino acids are asymmetrical molecules . For all standard amino acids, except glycine , the α-carbon is a chiral center . In the case of glycine,

3904-409: The two synthetic pathways is the diaminopimelic acid pathway; it consists of several enzymatic reactions that add carbon groups to aspartate to yield lysine: The serine family of amino acid includes: serine, cysteine , and glycine . Most microorganisms and plants obtain the sulfur for synthesizing methionine from the amino acid cysteine. Furthermore, the conversion of serine to glycine provides

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3968-577: The vitalism debate. However, the IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid as organic compounds. Other compounds lacking C-H bonds but traditionally considered organic include benzenehexol , mesoxalic acid , and carbon tetrachloride . Mellitic acid , which contains no C-H bonds, is considered a possible organic compound in Martian soil. Terrestrially, it, and its anhydride, mellitic anhydride , are associated with

4032-520: The α-carbon has two hydrogen atoms, thus adding symmetry to this molecule. With the exception of proline , all of the amino acids found in life have the L-isoform conformation. Proline has a functional group on the α-carbon that forms a ring with the amino group. One major step in amino acid biosynthesis involves incorporating a nitrogen group onto the α-carbon. In cells, there are two major pathways of incorporating nitrogen groups. One pathway involves

4096-445: Was known to occur only in the urine of living organisms. Wöhler's experiments were followed by many others, in which increasingly complex "organic" substances were produced from "inorganic" ones without the involvement of any living organism, thus disproving vitalism. Although vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds. The modern meaning of organic compound

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