Carbohydrates fructose

The end result of the photochemical part of photosynthesis is the formation of 02, NADPH, and ATP. Much of the oxygen is released to the atmosphere, but the NADPH and ATP are utilized in a series of dark reactions that achieve the reduction of carbon dioxide to the level of a carbohydrate (fructose). A balanced equation is... 

The next component is malic acid, unfortunately not always very reliably quantified In the particular case of the sethoxydim profile it appears as a blank Then come shikimic acid and quinic acid The next three bars symbolize the plant sterols ceuapesterol, stigmasterol and fi-sitosterol Then follows a peak (T-La), tentatively identified as a C4 -sugar lactone The next three peaks are the carbohydrates fructose, glucose and sucrose ... 

Fermented carbohydrates + fructose, glucose, sucrose, raffinose d galactose, maltose, melibiose, starch — lactose, trehalose ... 

Molisch s test A general test for carbohydrates. The carbohydrate is dissolved in water, alcoholic 1-naphthol added, and concentrated sulphuric acid poured down the side of the tube. A deep violet ring is formed at the junction of the liquids. A modification, the rapid furfural test , is used to distinguish between glucose and fructose. A mixture of the sugar, 1-naphthol, and concentrated hydrochloric acid is boiled. With fructose and saccharides containing fructose a violet colour is produced immediately the solution boils. With glucose the appearance of the colour is slower. 

Carbohydrates may be divided into monosaccharides, disaccharides and polysaccharides. The monosaccharides under certain conditions react as polyhydroxy-aldehydes or polyhydroxy-ketones two important representatives are glucose CjHjjO (an aldose) and fructose (laevulose) CgHuO, (a ketose). Upon hydrolysis di- and polysaccharides 3deld ultimately monosaccharides. Common disaccharides are sucrose, lactose and maltose (all of molecular formula C,2H2. 0,), whilst starch, dextrin and cellulose, (CjHjoOj), in which n > 4, are typical polysaccharides. 

The following simple test distinguishes fructose from all other carbohydrates. Upon heating a little fructose with dilute cobalt chloride solution, cooling and treating with a little ammonia solution, a violet to purple colour is developed, - the colour gradually fades and must be observed immediately after the addition of the ammonia solution. Green cobalt hydroxide is formed with all other carbohydrates. 

Up to this point all our attention has been directed toward aldoses carbohydrates hav ing an aldehyde function in their open chain form Aldoses are more common than ketoses and their role m biological processes has been more thoroughly studied Nev ertheless a large number of ketoses are known and several of them are pivotal inter mediates m carbohydrate biosynthesis and metabolism Examples of some ketoses include d nbulose l xylulose and d fructose... 

Carbohydrates undergo a number of isomerization and degradation reactions under both laboratory and physiological conditions For example a mixture of glucose fructose and mannose results when any one of them is treated with aqueous base This reaction can be understood by examining the consequences of enohzation of glucose... 

In long-wavelength UV light (2 = 365 nm) carbohydrates, e.g. glucose, fructose and lactose, yield pale blue fluorescent derivatives on a weakly fluorescent background. In situ quantitation can be performed at = 365 nm and 2fi = 546 nm (monochromatic filter M 546) [19]. Further differentiation can be achieved by spraying afterwards with p-anisidine-phosphoric acid reagent [8]. 

From the organochemical point of view, carbohydrates/polysaccharides are more or less substituted polyhydroxy aldehydes (e.g., glucose—>glucans) or polyhydroxy ketons (e.g., fructose-n fructans). From the physicochemical point of view, an enormous heterogeneity also exists in... 

The most familiar of all the carbohydrates is sucrose—common table sugar. Sucrose is a disacchar ide in which D-glucose and D-fructose are joined at then anomeric carbons by a glycosidic bond (Figure 25.7). Its chemical composition is the same ine-spective of its source sucrose from cane and sucrose from sugar beets are chemically identical. Because sucrose does not have a free anomeric hydroxyl group, it does not undergo mutarotation. 

One of the steps in the biological pathway for carbohydrate metabolism is the conversion of fructose 1,6-bisphosphate into dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. Propose a mechanism for the transformation. 

Monosaccharides, which cannot be broken down chemically to simpler carbohydrates. The most familiar monosaccharides contain either six carbon atoms per molecule (glucose, fructose, galactose,.. . ) or five (ribose, arabinose,.. . ). 

Combined electrolyte solutions are available for oral and IV administration. The IV solutions contain various electrolytes and dextrose. The amount of electrolytes, given as milliequivalents per liter (mEq/L), also varies. The IV solutions are used to replace fluid and electrolytes that have been lost and to provide calories by means of their carbohydrate content. Examples of IV electrolyte solutions are dextrose 5% with 0.9% NaCl, lactated Ringer s injection, Plasma-Lyte, and 10% Travert (invert sugar—a combination of equal parts of fructose and dextrose) and Electrolyte No. 2. 

FIGURE 4-15 Cyclic voltanmiograms for 1.5 x 10 3 M ribose (a), glucose (b), galactose (c), and fructose (d) recorded at a Ru02-modified carbon-paste electrode. Dotted lines were obtained in carbohydrate-free solutions. (Reproduced with permission from reference 50.)... 

D-Fructose is the sweetest sugar known in naturally occurring carbohydrates, and its intense sweetness is produced only by ) -D-fructopyranose. "... 

The digestible dietary carbohydrates yield glucose, galactose, and fructose that are transported via the hepatic portal vein to the hver where galactose and fructose are readily converted to glucose (Chapter 20). 

Cellulose and starch are macromolecules with empirical formulas that resemble hydrated carbon, CX (H2 0)y, where x and y are integers. The monomers from which these macromolecules are consfructed are sugars such as glucose and fructose. These monomers and macromolecules are the carbohydrates. Structurally, carbohydrates are very different from simple combinations of carbon and water. Even the smallest carbohydrates contain carbon chains with hydrogen atoms, OH groups, and occasional ether linkages. 

Carbohydrates are an important food source for most organisms. Glucose, fructose, and sucrose are small carbohydrate molecules that can be broken down rapidly to provide quick energy for cells. Large amounts of energy are stored in carbohydrate macromolecules called polysaccharides. For example, glycogen is a polysaccharide used... 

Defaye, K. and Garcia Fernandez, J.M., Protonic and thermal activation of sucrose an the oligosaccaride composition of caramel. Carbohydrate Res., 256, Cl, 1994. Ratsimba, V. et al.. Qualitative and qnantitative evaluation of mono- and disaccharides in D-fructose, D-glucose and sucrose caramels by gas-liquid chromatography-mass spectrometry di-D-fructose dianhydrides as tracers of caramel authenticity, J. Chro-matogr. A, 844, 283, 1999. 

The Enzymes II (E-IIs) of the phosphoenolpyruvate (P-enolpyruvate)-dependent phosphotransferase system (PTS) are carbohydrate transporters found only in prokaryotes. They not only transport hexoses and hexitols, but also pentitols and disaccharides. The PTS substrates are listed in Table I. The abbreviations used (as superscripts) throughout the text for these substrates are as follows Bgl, jS-gluco-side Cel, cellobiose Fru, fructose Glc, glucose Gut, glucitol Lac, lactose Man, mannose Mtl, mannitol Nag, iV-acetylglucosamine Scr, sucrose Sor, sorbose Xtl, xylitol. 

The melting points of carbohydrates (sugars) are not usually sharp and they are perhaps best expressed as decomposition points, t The small capital letter prefix refers to configuration, relat to D- lyceraldehyde, and not to the direction of optical rotation. The sign of optical rotation is expressed as (+) and (—) or as d and I or by the words dtxtro and loevo. Thus we have d-(—)-fructose and ,-(+).arabinose. 

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