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70-460: 4YB9 , 4YBQ 6518 56485 ENSG00000142583 ENSMUSG00000028976 P22732 Q9WV38 NM_001135585 NM_003039 NM_001328619 NM_001328620 NM_001328621 NM_019741 NP_001129057 NP_001315548 NP_001315549 NP_001315550 NP_003030 NP_062715 GLUT5 is a fructose transporter expressed on the apical border of enterocytes in the small intestine . GLUT5 allows for fructose to be transported from

140-424: A chemical compound ; the concept is most readily understood when considering pure chemical substances . It follows from their being composed of fixed proportions of two or more types of atoms that chemical compounds can be converted, via chemical reaction , into compounds or substances each having fewer atoms. A chemical formula is a way of expressing information about the proportions of atoms that constitute

210-419: A solid-state reaction , or the electron transfer reaction of reactive metals with reactive non-metals, such as halogen gases. Ionic compounds typically have high melting and boiling points , and are hard and brittle . As solids they are almost always electrically insulating , but when melted or dissolved they become highly conductive , because the ions are mobilized. An intermetallic compound

280-453: A buildup of Krebs cycle intermediates. Accumulated citrate can be transported from the mitochondria into the cytosol of hepatocytes , converted to acetyl CoA by citrate lyase and directed toward fatty acid synthesis. In addition, DHAP can be converted to glycerol 3-phosphate, providing the glycerol backbone for the triglyceride molecule. Triglycerides are incorporated into very-low-density lipoproteins (VLDL), which are released from

350-474: A component of total and free sugars." The word "fructose" was coined in 1857 from the Latin for fructus (fruit) and the generic chemical suffix for sugars, -ose . It is also called fruit sugar and levulose or laevulose, due to its ability to rotate plane polarised light in a laevorotary fashion (anti-clockwise/to the left) when a beam is shone through it in solution. Likewise, dextrose (an isomer of glucose)

420-412: A continuous three-dimensional network, usually in a crystalline structure . Ionic compounds containing basic ions hydroxide (OH ) or oxide (O ) are classified as bases. Ionic compounds without these ions are also known as salts and can be formed by acid–base reactions . Ionic compounds can also be produced from their constituent ions by evaporation of their solvent , precipitation , freezing ,

490-516: A disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using the standard chemical symbols with numerical subscripts . Many chemical compounds have a unique CAS number identifier assigned by the Chemical Abstracts Service . Globally, more than 350,000 chemical compounds (including mixtures of chemicals) have been registered for production and use. The term "compound"—with

560-541: A free monosaccharide or bound to glucose as sucrose, a disaccharide . Fructose, glucose, and sucrose may all be present in food; however, different foods will have varying levels of each of these three sugars. The sugar contents of common fruits and vegetables are presented in Table 1. In general, in foods that contain free fructose, the ratio of fructose to glucose is approximately 1:1; that is, foods with fructose usually contain about an equal amount of free glucose. A value that

630-493: A meal may reduce the glycemic response of the meal. Fructose-sweetened food and beverage products cause less of a rise in blood glucose levels than do those manufactured with either sucrose or glucose. Chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities ) containing atoms from more than one chemical element held together by chemical bonds . A molecule consisting of atoms of only one element

700-444: A meaning similar to the modern—has been used at least since 1661 when Robert Boyle's The Sceptical Chymist was published. In this book, Boyle variously used the terms "compound", "compounded body", "perfectly mixt body", and "concrete". "Perfectly mixt bodies" included for example gold, lead, mercury, and wine. While the distinction between compound and mixture is not so clear, the distinction between element and compound

770-413: A monosaccharide (free fructose) or as a unit of a disaccharide (sucrose). Free fructose is a ketonic simple sugar and one of the three dietary monosaccharides absorbed directly by the intestine. When fructose is consumed in the form of sucrose, it is digested (broken down) and then absorbed as free fructose. As sucrose comes into contact with the membrane of the small intestine, the enzyme sucrase catalyzes

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840-566: A particular chemical compound, using chemical symbols for the chemical elements, and subscripts to indicate the number of atoms involved. For example, water is composed of two hydrogen atoms bonded to one oxygen atom: the chemical formula is H 2 O. In the case of non-stoichiometric compounds , the proportions may be reproducible with regard to their preparation, and give fixed proportions of their component elements, but proportions that are not integral [e.g., for palladium hydride , PdH x (0.02 < x < 0.58)]. Chemical compounds have

910-550: A positive relationship between the intake of dietary sugars, in isocaloric exchange with other macronutrients, and any of the chronic metabolic diseases or pregnancy-related endpoints assessed" but advised "the intake of added and free sugars should be as low as possible in the context of a nutritionally adequate diet." When fructose is consumed in excess as a sweetening agent in foods or beverages, it may be associated with increased risk of obesity, diabetes, and cardiovascular disorders that are part of metabolic syndrome . Fructose

980-496: A positively charged cation . The nonmetal will gain the electrons from the metal, making the nonmetal a negatively charged anion . As outlined, ionic bonds occur between an electron donor, usually a metal, and an electron acceptor, which tends to be a nonmetal. Hydrogen bonding occurs when a hydrogen atom bonded to an electronegative atom forms an electrostatic connection with another electronegative atom through interacting dipoles or charges. A compound can be converted to

1050-513: A roughly equal ratio of fructose to glucose, with minor differences. HFCS has simply replaced sucrose as a sweetener. Therefore, despite the changes in the sweetener consumption, the ratio of glucose to fructose intake has remained relatively constant. Providing 368 kcal per 100 grams of dry powder (table), fructose has 95% the caloric value of sucrose by weight. Fructose powder is 100% carbohydrates and supplies no other nutrients in significant amount (table). Fructose exists in foods either as

1120-447: A solid state dependent on how low the temperature of the environment is. A covalent bond , also known as a molecular bond, involves the sharing of electrons between two atoms. Primarily, this type of bond occurs between elements that fall close to each other on the periodic table of elements , yet it is observed between some metals and nonmetals. This is due to the mechanism of this type of bond. Elements that fall close to each other on

1190-469: A unique and defined chemical structure held together in a defined spatial arrangement by chemical bonds . Chemical compounds can be molecular compounds held together by covalent bonds , salts held together by ionic bonds , intermetallic compounds held together by metallic bonds , or the subset of chemical complexes that are held together by coordinate covalent bonds . Pure chemical elements are generally not considered chemical compounds, failing

1260-461: A unit of g (gram) are based on 100 g of a food item. The fructose/glucose ratio is calculated by dividing the sum of free fructose plus half sucrose by the sum of free glucose plus half sucrose. Fructose is also found in the manufactured sweetener , high-fructose corn syrup (HFCS), which is produced by treating corn syrup with enzymes , converting glucose into fructose. The common designations for fructose content, HFCS-42 and HFCS-55, indicate

1330-859: Is a compound with one molecule of glucose covalently linked to one molecule of fructose. All forms of fructose, including those found in fruits and juices, are commonly added to foods and drinks for palatability and taste enhancement, and for browning of some foods, such as baked goods. As of 2004, about 240,000 tonnes of crystalline fructose were being produced annually. Excessive consumption of sugars, including fructose, (especially from sugar-sweetened beverages) may contribute to insulin resistance , obesity , elevated LDL cholesterol and triglycerides , leading to metabolic syndrome . The European Food Safety Authority (EFSA) stated in 2011 that fructose may be preferable over sucrose and glucose in sugar-sweetened foods and beverages because of its lower effect on postprandial blood sugar levels, while also noting

1400-465: Is a better substrate for glycogen synthesis than glucose and that glycogen replenishment takes precedence over triglyceride formation. Once liver glycogen is replenished, the intermediates of fructose metabolism are primarily directed toward triglyceride synthesis. Carbons from dietary fructose are found in both the free fatty acid and glycerol moieties of plasma triglycerides. High fructose consumption can lead to excess pyruvate production, causing

1470-445: Is a central theme. Quicksilver ... with Aqua fortis will be brought into a ... white Powder ... with Sulphur it will compose a blood-red and volatile Cinaber. And yet out of all these exotick Compounds, we may recover the very same running Mercury. Boyle used the concept of "corpuscles"—or "atomes", as he also called them—to explain how a limited number of elements could combine into a vast number of compounds: If we assigne to

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1540-403: Is a type of metallic alloy that forms an ordered solid-state compound between two or more metallic elements. Intermetallics are generally hard and brittle, with good high-temperature mechanical properties. They can be classified as stoichiometric or nonstoichiometric intermetallic compounds. A coordination complex consists of a central atom or ion, which is usually metallic and is called

1610-427: Is above 1 indicates a higher proportion of fructose to glucose and below 1 a lower proportion. Some fruits have larger proportions of fructose to glucose compared to others. For example, apples and pears contain more than twice as much free fructose as glucose, while for apricots the proportion is less than half as much fructose as glucose. Apple and pear juices are of particular interest to pediatricians because

1680-493: Is capable of increasing the abundance and functional activity of GLUT5, fructose transporter, in skeletal muscle cells. The initial catabolism of fructose is sometimes referred to as fructolysis , in analogy with glycolysis , the catabolism of glucose. In fructolysis, the enzyme fructokinase initially produces fructose 1-phosphate , which is split by aldolase B to produce the trioses dihydroxyacetone phosphate (DHAP) and glyceraldehyde . Unlike glycolysis, in fructolysis

1750-589: Is discussed in greater detail in the Health Effects section. Table 1 also shows the amount of sucrose found in common fruits and vegetables. Sugarcane and sugar beet have a high concentration of sucrose, and are used for commercial preparation of pure sucrose. Extracted cane or beet juice is clarified, removing impurities; and concentrated by removing excess water. The end product is 99.9%-pure sucrose. Sucrose-containing sugars include common white sugar and powdered sugar , as well as brown sugar . All data with

1820-617: Is given its name due to its ability to rotate plane polarised light in a dextrorotary fashion (clockwise/to the right). Fructose is a 6-carbon polyhydroxyketone. Crystalline fructose adopts a cyclic six-membered structure, called β- d -fructopyranose, owing to the stability of its hemiketal and internal hydrogen-bonding. In solution, fructose exists as an equilibrium mixture of the tautomers β- d -fructo pyranose , β- d -fructo furanose , α- d -fructofuranose, α- d -fructopyranose and keto - d -fructose (the non-cyclic form). The distribution of d -fructose tautomers in solution

1890-526: Is ingested as part of the disaccharide sucrose, absorption capacity is much higher because fructose exists in a 1:1 ratio with glucose. It appears that the GLUT5 transfer rate may be saturated at low levels, and absorption is increased through joint absorption with glucose. One proposed mechanism for this phenomenon is a glucose-dependent cotransport of fructose. In addition, fructose transfer activity increases with dietary fructose intake. The presence of fructose in

1960-401: Is inhibitory. Fructose absorption by GLUT5 can be investigated using intestinal organoids. Click on genes, proteins and metabolites below to link to respective articles. This membrane protein –related article is a stub . You can help Misplaced Pages by expanding it . Fructose Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847. The name "fructose"

2030-493: Is neutral overall, but consists of positively charged ions called cations and negatively charged ions called anions . These can be simple ions such as the sodium (Na ) and chloride (Cl ) in sodium chloride , or polyatomic species such as the ammonium ( NH 4 ) and carbonate ( CO 3 ) ions in ammonium carbonate . Individual ions within an ionic compound usually have multiple nearest neighbours, so are not considered to be part of molecules, but instead part of

2100-471: Is not absorbed in the small intestine, it is transported into the large intestine, where it is fermented by the colonic flora. Hydrogen is produced during the fermentation process and dissolves into the blood of the portal vein . This hydrogen is transported to the lungs, where it is exchanged across the lungs and is measurable by the hydrogen breath test. The colonic flora also produces carbon dioxide, short-chain fatty acids , organic acids, and trace gases in

2170-549: Is not due to anomeric distribution but a decrease in the absolute sweetness of sucrose at higher temperatures. The sweetness of fructose is perceived earlier than that of sucrose or glucose, and the taste sensation reaches a peak (higher than that of sucrose), and diminishes more quickly than that of sucrose. Fructose can also enhance other flavors in the system. Fructose exhibits a sweetness synergy effect when used in combination with other sweeteners. The relative sweetness of fructose blended with sucrose, aspartame, or saccharin

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2240-454: Is often further concentrated from these sources. The highest dietary sources of fructose, besides pure crystalline fructose, are foods containing white sugar (sucrose), high-fructose corn syrup , agave nectar , honey , molasses , maple syrup , fruit and fruit juices , as these have the highest percentages of fructose (including fructose in sucrose) per serving compared to other common foods and ingredients. Fructose exists in foods either as

2310-408: Is perceived to be greater than the sweetness calculated from individual components. Fructose has higher water solubility than other sugars, as well as other sugar alcohols. Fructose is, therefore, difficult to crystallize from an aqueous solution. Sugar mixes containing fructose, such as candies, are softer than those containing other sugars because of the greater solubility of fructose. Fructose

2380-493: Is quicker to absorb moisture and slower to release it to the environment than sucrose, glucose, or other nutritive sweeteners. Fructose is an excellent humectant and retains moisture for a long period of time even at low relative humidity (RH). Therefore, fructose can contribute a more palatable texture, and longer shelf life to the food products in which it is used. Fructose has a greater effect on freezing point depression than disaccharides or oligosaccharides, which may protect

2450-426: Is related to several variables, such as solvent and temperature. d -Fructopyranose and d -fructofuranose distributions in water have been identified multiple times as roughly 70% fructopyranose and 22% fructofuranose. Fructose may be anaerobically fermented by yeast and bacteria . Yeast enzymes convert sugar ( sucrose , glucose , and fructose, but not lactose ) to ethanol and carbon dioxide . Some of

2520-418: Is the 6-membered ring form of fructose that is sweeter; the 5-membered ring form tastes about the same as usual table sugar. Warming fructose leads to formation of the 5-membered ring form. Therefore, the relative sweetness decreases with increasing temperature. However, it has been observed that the absolute sweetness of fructose is identical at 5 °C as 50 °C and thus the relative sweetness to sucrose

2590-639: Is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction , which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds ; ionic compounds are held together by ionic bonds ; intermetallic compounds are held together by metallic bonds ; coordination complexes are held together by coordinate covalent bonds . Non-stoichiometric compounds form

2660-452: The coordination centre , and a surrounding array of bound molecules or ions, that are in turn known as ligands or complexing agents. Many metal-containing compounds, especially those of transition metals , are coordination complexes. A coordination complex whose centre is a metal atom is called a metal complex of d block element. Compounds are held together through a variety of different types of bonding and forces. The differences in

2730-418: The intestinal lumen into the enterocyte by facilitated diffusion due to fructose's high concentration in the intestinal lumen. GLUT5 is also expressed in skeletal muscle , testis, kidney, fat tissue (adipocytes), and brain. Fructose malabsorption or Dietary Fructose Intolerance is a dietary disability of the small intestine , where the amount of fructose carrier in enterocytes is deficient. In humans

2800-449: The oxygen molecule (O 2 ); or it may be heteronuclear , a chemical compound composed of more than one element, as with water (two hydrogen atoms and one oxygen atom; H 2 O). A molecule is the smallest unit of a substance that still carries all the physical and chemical properties of that substance. An ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding . The compound

2870-896: The Corpuscles, whereof each Element consists, a peculiar size and shape ... such ... Corpuscles may be mingled in such various Proportions, and ... connected so many ... wayes, that an almost incredible number of ... Concretes may be compos’d of them. In his Logick , published in 1724, the English minister and logician Isaac Watts gave an early definition of chemical element, and contrasted element with chemical compound in clear, modern terms. Among Substances, some are called Simple, some are Compound ... Simple Substances ... are usually called Elements, of which all other Bodies are compounded: Elements are such Substances as cannot be resolved, or reduced, into two or more Substances of different Kinds. ... Followers of Aristotle made Fire, Air, Earth and Water to be

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2940-459: The Earth. Other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. A molecule may be homonuclear , that is, it consists of atoms of one chemical element, as with two atoms in

3010-525: The GLUT2 transporter has a greater capacity for transporting fructose, and, therefore, the majority of fructose is transported out of the enterocyte through GLUT2. The absorption capacity for fructose in monosaccharide form ranges from less than 5 g to 50 g (per individual serving) and adapts with changes in dietary fructose intake. Studies show the greatest absorption rate occurs when glucose and fructose are administered in equal quantities. When fructose

3080-513: The GLUT5 protein is encoded by the SLC2A5 gene . Fructose uptake rate by GLUT5 is significantly reduced by diabetes mellitus , hypertension , obesity , fructose malabsorption , and inflammation . However, age-related changes in fructose intake capability are not explained by the rate of expression of GLUT5. The absorption of fructose in the simultaneous presence of glucose is improved, while sorbitol

3150-524: The Truth ;; tho' they are not all agreed ... Compound Substances are made up of two or more simple Substances ... So a Needle is simple Body, being made only of Steel; but a Sword or a Knife is a compound because its ... Handle is made of Materials different from the Blade. Any substance consisting of two or more different types of atoms ( chemical elements ) in a fixed stoichiometric proportion can be termed

3220-482: The carbon dioxide produced during fermentation will remain dissolved in water, where it will reach equilibrium with carbonic acid . The dissolved carbon dioxide and carbonic acid produce the carbonation in some fermented beverages , such as champagne . Fructose undergoes the Maillard reaction , non-enzymatic browning, with amino acids . Because fructose exists to a greater extent in the open-chain form than does glucose,

3290-417: The cleavage of sucrose to yield one glucose unit and one fructose unit, which are then each absorbed. After absorption, it enters the hepatic portal vein and is directed toward the liver. The mechanism of fructose absorption in the small intestine is not completely understood. Some evidence suggests active transport , because fructose uptake has been shown to occur against a concentration gradient. However,

3360-539: The development of HFCS, a significant shift occurred in the type of sweetener consumption in certain countries, particularly the United States. Contrary to the popular belief, however, with the increase of HFCS consumption, the total fructose intake relative to the total glucose intake has not dramatically changed. Granulated sugar is 99.9%-pure sucrose, which means that it has equal ratio of fructose to glucose. The most commonly used forms of HFCS, HFCS-42, and HFCS-55, have

3430-400: The fixed ratios. Many solid chemical substances—for example many silicate minerals —are chemical substances, but do not have simple formulae reflecting chemically bonding of elements to one another in fixed ratios; even so, these crystalline substances are often called " non-stoichiometric compounds ". It may be argued that they are related to, rather than being chemical compounds, insofar as

3500-508: The four Elements, of which all earthly Things were compounded; and they suppos'd the Heavens to be a Quintessence, or fifth sort of Body, distinct from all these : But, since experimental Philosophy ... have been better understood, this Doctrine has been abundantly refuted. The Chymists make Spirit, Salt, Sulphur, Water and Earth to be their five Elements, because they can reduce all terrestrial Things to these five : This seems to come nearer

3570-437: The future, may become part of a low-cost, carbon-neutral system to produce replacements for petrol and diesel from plants. The primary reason that fructose is used commercially in foods and beverages, besides its low cost, is its high relative sweetness. It is the sweetest of all naturally occurring carbohydrates . The relative sweetness of fructose has been reported in the range of 1.2–1.8 times that of sucrose. However, it

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3640-404: The gluconeogenic pathway leading to glycogen synthesis as well as fatty acid and triglyceride synthesis. The resultant glyceraldehyde formed by aldolase B then undergoes phosphorylation to glyceraldehyde 3-phosphate. Increased concentrations of DHAP and glyceraldehyde 3-phosphate in the liver drive the gluconeogenic pathway toward glucose and subsequent glycogen synthesis. It appears that fructose

3710-402: The high concentrations of free fructose in these juices can cause diarrhea in children. The cells ( enterocytes ) that line children's small intestines have less affinity for fructose absorption than for glucose and sucrose. Unabsorbed fructose creates higher osmolarity in the small intestine, which draws water into the gastrointestinal tract, resulting in osmotic diarrhea. This phenomenon

3780-579: The initial stages of the Maillard reaction occur more rapidly than with glucose. Therefore, fructose has potential to contribute to changes in food palatability , as well as other nutritional effects, such as excessive browning, volume and tenderness reduction during cake preparation, and formation of mutagenic compounds. Fructose readily dehydrates to give hydroxymethylfurfural ("HMF", C 6 H 6 O 3 ), which can be processed into liquid dimethylfuran ( C 6 H 8 O ). This process, in

3850-599: The integrity of cell walls of fruit by reducing ice crystal formation. However, this characteristic may be undesirable in soft-serve or hard-frozen dairy desserts. Fructose increases starch viscosity more rapidly and achieves a higher final viscosity than sucrose because fructose lowers the temperature required during gelatinizing of starch , causing a greater final viscosity. Although some artificial sweeteners are not suitable for home baking, many traditional recipes use fructose. Natural sources of fructose include fruits, vegetables (including sugar cane), and honey. Fructose

3920-401: The liver by the GLUT2 transporter. Fructose and galactose are phosphorylated in the liver by fructokinase ( K m = 0.5 mM) and galactokinase (K m = 0.8 mM), respectively. By contrast, glucose tends to pass through the liver (K m of hepatic glucokinase = 10 mM) and can be metabolised anywhere in the body. Uptake of fructose by the liver is not regulated by insulin. However, insulin

3990-589: The liver destined toward peripheral tissues for storage in both fat and muscle cells. In 2022, the European Food Safety Authority stated that there is research evidence that fructose and other added free sugars may be associated with increased risk of several chronic diseases: the risk is moderate for obesity and dyslipidemia (more than 50%), and low for non-alcoholic fatty liver disease , type 2 diabetes (from 15% to 50%) and hypertension . EFSA further stated that clinical research did "not support

4060-411: The lumen causes increased mRNA transcription of GLUT5, leading to increased transport proteins. High-fructose diets (>2.4 g/kg body wt) increase the transport proteins within three days of intake. Several studies have measured the intestinal absorption of fructose using the hydrogen breath test . These studies indicate that fructose is not completely absorbed in the small intestine. When fructose

4130-456: The majority of research supports the claim that fructose absorption occurs on the mucosal membrane via facilitated transport involving GLUT5 transport proteins. Since the concentration of fructose is higher in the lumen, fructose is able to flow down a concentration gradient into the enterocytes , assisted by transport proteins. Fructose may be transported out of the enterocyte across the basolateral membrane by either GLUT2 or GLUT5, although

4200-683: The metabolism of fructose is the phosphorylation of fructose to fructose 1-phosphate by fructokinase, thus trapping fructose for metabolism in the liver. Fructose 1-phosphate then undergoes hydrolysis by aldolase B to form DHAP and glyceraldehydes; DHAP can either be isomerized to glyceraldehyde 3-phosphate by triosephosphate isomerase or undergo reduction to glycerol 3-phosphate by glycerol 3-phosphate dehydrogenase. The glyceraldehyde produced may also be converted to glyceraldehyde 3-phosphate by glyceraldehyde kinase or further converted to glycerol 3-phosphate by glycerol 3-phosphate dehydrogenase. The metabolism of fructose at this point yields intermediates in

4270-454: The percentage of fructose present in HFCS. HFCS-55 is commonly used as a sweetener for soft drinks , whereas HFCS-42 is used to sweeten processed foods, breakfast cereals , bakery foods, and some soft drinks. for HFCS, and USDA for fruits and vegetables and the other refined sugars. Cane and beet sugars have been used as the major sweetener in food manufacturing for centuries. However, with

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4340-536: The periodic table tend to have similar electronegativities , which means they have a similar affinity for electrons. Since neither element has a stronger affinity to donate or gain electrons, it causes the elements to share electrons so both elements have a more stable octet . Ionic bonding occurs when valence electrons are completely transferred between elements. Opposite to covalent bonding, this chemical bond creates two oppositely charged ions. The metals in ionic bonding usually lose their valence electrons, becoming

4410-503: The potential downside that "high intakes of fructose may lead to metabolic complications such as dyslipidaemia , insulin resistance, and increased visceral adiposity". The UK's Scientific Advisory Committee on Nutrition in 2015 disputed the claims of fructose causing metabolic disorders, stating that "there is insufficient evidence to demonstrate that fructose intake, at levels consumed in the normal UK diet, leads to adverse health outcomes independent of any effects related to its presence as

4480-455: The presence of unabsorbed fructose. The presence of gases and organic acids in the large intestine causes gastrointestinal symptoms such as bloating, diarrhea, flatulence, and gastrointestinal pain. Exercise immediately after consumption can exacerbate these symptoms by decreasing transit time in the small intestine, resulting in a greater amount of fructose emptied into the large intestine. All three dietary monosaccharides are transported into

4550-422: The triose glyceraldehyde lacks a phosphate group . A third enzyme, triokinase , is therefore required to phosphorylate glyceraldehyde, producing glyceraldehyde 3-phosphate . The resulting trioses are identical to those obtained in glycolysis and can enter the gluconeogenic pathway for glucose or glycogen synthesis, or be further catabolized through the lower glycolytic pathway to pyruvate . The first step in

4620-494: The two or more atom requirement, though they often consist of molecules composed of multiple atoms (such as in the diatomic molecule H 2 , or the polyatomic molecule S 8 , etc.). Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service (CAS): its CAS number . There is varying and sometimes inconsistent nomenclature differentiating substances, which include truly non-stoichiometric examples, from chemical compounds, which require

4690-455: The types of bonds in compounds differ based on the types of elements present in the compound. London dispersion forces are the weakest force of all intermolecular forces . They are temporary attractive forces that form when the electrons in two adjacent atoms are positioned so that they create a temporary dipole . Additionally, London dispersion forces are responsible for condensing non polar substances to liquids, and to further freeze to

4760-421: The variability in their compositions is often due to either the presence of foreign elements trapped within the crystal structure of an otherwise known true chemical compound , or due to perturbations in structure relative to the known compound that arise because of an excess of deficit of the constituent elements at places in its structure; such non-stoichiometric substances form most of the crust and mantle of

4830-460: Was coined in 1857 by the English chemist William Allen Miller . Pure, dry fructose is a sweet, white, odorless, crystalline solid, and is the most water-soluble of all the sugars. Fructose is found in honey , tree and vine fruits, flowers, berries , and most root vegetables . Commercially, fructose is derived from sugar cane , sugar beets , and maize . High-fructose corn syrup is a mixture of glucose and fructose as monosaccharides. Sucrose

4900-518: Was found to increase triglycerides in type-2 but not type-1 diabetes and moderate use of it has previously been considered acceptable as a sweetener for diabetics, possibly because it does not trigger the production of insulin by pancreatic β cells . For a 50 gram reference amount, fructose has a glycemic index of 23, compared with 100 for glucose and 60 for sucrose. Fructose is also 73% sweeter than sucrose at room temperature, allowing diabetics to use less of it per serving. Fructose consumed before

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