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Alpha And Beta Glucose Structure

Help: Question About Beta Glucose Watch

Help: Question About Beta Glucose Watch

You need to look at the differences between alpha and beta glucose. Here are 2 alpha glucose molecules. You should be able to see that during condensation, they can easily all bond the same way up, as their hydroxyl groups are on the bottom in both molecules. This means that alpha glucose can form long polymers where all of the molecules have the same orientation (facing upwards). This causes either a helical (amylose) or branched (amylopectin) structure, and the polymer is not straight. This is because each monomer of glucose is "bent" as shown by the bold lines on the bottom of the molecule, think of it like joining together many slightly bent pieces of wire in the same direction - you would make a helix. Since the hydroxyl groups on each molecule are on opposite sides, they can only bond with one of them "upside down". This means that the beta glucose polymer will have a very different structure, as every other CH2OH group is on the opposite side. This means that the bending effects seen in starch are not seen, as the molecules are not all bending the same way. Think of it like joining together many bent pieces of wire, but each piece is bent in opposite directions, so overall they make a straight line (or a kind of zigzag). You need to look at the differences between alpha and beta glucose. Here are 2 alpha glucose molecules. You should be able to see that during condensation, they can easily all bond the same way up, as their hydroxyl groups are on the bottom in both molecules. This means that alpha glucose can form long polymers where all of the molecules have the same orientation (facing upwards). This causes either a helical (amylose) or branched (amylopectin) structure, and the polymer is not straight. This is because each monomer of glucose is "bent" as shown Continue reading >>

What's The Difference Between Alpha-glucose And Beta-glucose?

What's The Difference Between Alpha-glucose And Beta-glucose?

What's the difference between alpha-glucose and beta-glucose? beta D-glucose units makes up the structure of cellulose polysaccharides while alpha D-glucose units makes up the structure of polysaccharides starch. user9873 Nov 18 '14 at 14:12 $\alpha$-D-glucose and $\beta$-D-glucose are stereoisomers - they differ in the 3-dimensional configuration of atoms/groups at one or more positions. Note that the structures are almost identical, except that in the $\alpha$ form, the $\ce{OH}$ group on the far right is down, and, in the $\beta$ form, the $\ce{OH}$ group on the far right is up. More specifically, they are a class of stereoisomer called an anomer . Anomers are capable of interconverting in solution. All cyclic structures of monosaccharides exhibit anomeric $\alpha$ (down) and $\beta$ (up) versions. These differences occur at the anomeric acetal carbon (the only carbon with two $\ce{C-O}$ bonds. These two forms exist because all monosaccharides also have an open-chain form with one fewer stereocenter. When the chain closes to the cyclic structure, the aldehyde or ketone carbon becomes a stereocenter , and it can do so in either configuration. One configuration is preferred ($\beta$), but both exist. In the presence of acid or base (although water can fulfill this role if need be), the two anomers interconvert through the open form until dynamic equilibrium is established. The mechanism below starts with $\alpha$ in the upper left and finishes with $\beta$ in the lower right. The open-chain form is in the middle. Just to add, in the L-configuration, the situation is reversed, since you draw the CH2OH below the ring in the Haworth projection. In both cases, the structure is when the relevant groups are on the same side of the ring, and when they're on opposite sides. H Continue reading >>

Differences Between Alpha And Beta Glucose

Differences Between Alpha And Beta Glucose

Differences Between Alpha and Beta Glucose Categorized under Chemistry | Differences Between Alpha and Beta Glucose Encountering the term glucose makes us think of something sweet, which is, of course, true. If you remember what you studied during your biology or chemistry class, glucose is a form of carbohydrate; and carbohydrates give us the energy we need throughout the day. For us humans, glucose is considered the most important, simple sugar because it is a very essential factor in our metabolism. Though glucose is called a simple sugar, its chemistry is really complex. Glucose, which is oftentimes referred to as dextrose, is made up of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. When combined, it can take the form of a variety of arrangements; thus isomers are born. Among the first two isomers that chemists discovered were the alpha glucose and the beta glucose. Both fall under the category of glucose, but what are the differences between these two? If we are to compare their chemical structures, alpha glucose and beta glucose only differ in the way each carbon, hydrogen, and oxygen atoms are attached to one another. Though they have the same chemical composition, the way their atoms combine gives you two different structures. If we are to describe the molecules present in the alpha glucose, they are compressed but can be easily taken apart. On the other hand, the beta glucose molecules are solidly packed; hence, they cannot be easily taken apart. In other words, the molecules of beta glucose are very stable. Chains of alpha glucose compose starch. Since the foundation of starch is alpha glucose, it can be easily broken down into simple sugars. Meanwhile, chains of beta glucose compose cellulose. Unlike starch, cellulose is not easy to break down; henc Continue reading >>

Ch25: Alpha And Beta Forms

Ch25: Alpha And Beta Forms

The cyclic forms of carbohydrates can exist in two forms, -and - based on the position of the substituentat the anomeric center. The two forms are sometimes described as "anomers" since they areisomersatthe anomeric center. To assign the cyclic form of a carbohydrate as the -or - form look at the relative positions ofthe -CH2OH group and -OH (or -OR) group at the anomeric center. In the - form, the exocyclic Ogroup at the anomeric center is on the opposite face to the-CH2OH group, and In the - form, the exocyclic Ogroup at the anomeric center is on the same face as the -CH2OHgroup. If a mixture of the - and -anomers are present, then this is often represented by using a "wavy" lineto represent the bond: In general the two forms are stable solids, but in solution they rapidlyequilibrate (see mutarotation). The following figures shows several representations of the - and - anomers of D-glucose. You should Manipulate the 3D JMOL images until you can confirm the important relationship. Dr. Ian Hunt , Department of Chemistry, University of Calgary Continue reading >>

Difference Between Alpha And Beta Glucose

Difference Between Alpha And Beta Glucose

Home Science Chemistry Biochemistry Difference Between Alpha and Beta Glucose Difference Between Alpha and Beta Glucose Glucose is a simple carbohydrate . It is a sugar that has a sweet taste. The molecular formula of glucose is C6H12O6. The structure of glucose can be given in different ways such as the Fischer projection, Haworth projection or Chair conformation. The most accurate way of the representing glucose is the chair confirmation, which is typically the most stable structure of most of the cyclic molecules. The major isomers of glucose include D-glucose and L-glucose. According to the chair confirmation, there are two isomers of D-glucose that can be found in nature. Those are alpha glucose and beta glucose. The main difference between alpha and beta glucose is that the OH group attached to the first carbon atom in alpha glucose is located on the same side as the CH2OH group whereas the OH group attached to the first carbon atom of in beta glucose is located on the opposite side from the CH2OH group. Key Terms: -Glycopyranose, -Glycopyranose, Alpha Glucose, Beta Glucose, Chair Confirmation, Glucopyranose, Glucose, Oxygen Bridge Alpha Glucose is an isomer of D-glucose whose OH group of the first carbon atom is located on the same side as the CH2OH group. Alpha glucose is a sugar. When considering the chair confirmation structure, alpha glucose is a cyclic structure having four OH groups attached to the main carbon chain. The cycle is formed through an Oxygen bridge. That means, two carbon atoms of the terminal of the main carbon chain are attached through an oxygen atom. The ring structure is not planar and is a 3D structure. In order to avoid any confusion, the chair confirmation of glucose is called glucopyranose. Therefore, alpha glucose is also known as -g Continue reading >>

Beta-glucose - The School Of Biomedical Sciences Wiki

Beta-glucose - The School Of Biomedical Sciences Wiki

Beta-glucose is a cyclic, six carbon sugar , formed from glucose , and can polymerise to make cellulose , an essential polysaccharide used in the structure of plants. Glucose is a simple monosaccharide , chemical formulae: C6H12O6, and is an important carbohydrate which can provide energy or structure to organisms through its various forms [1] . In glucose, carbons 2, 3, 4 and 5 each have a hydroxyl group , and the direction these groups come off their chiral carbon decides the type of monosaccharide. Two of the combinations give the two glucose stereoisomers : D and L. These two isomers are mirror images of each other [2] . Other arrangements of the hydroxyl groups give different sugars, and all of these different sugars are epimers of each other. Glucose can form a cyclic structure by a reaction between C1 and C2. The cyclic version can come in two forms for each type of glucose: alpha and beta [3] .These two isomers exist because the formation of cyclic glucose creates an asymmetric carbon at C1. This stereoisomerism at C1 is the cause for the two forms. Repeated condensation reactions between C1 and C4 of two D-beta-glucose molecules forms a covalent glycosidic bond , creating a disaccharide , and with further polymerising can form cellulose - the most abundant organic molecule on Earth [4] . Cellulose is formed by 1,4 glycosidic bonds between hundreds of D-beta-glucose molecules and hydrogen bonds between the layers of the polysaccharide . This creates a highly organised crystalline structure, which plants use to maintain cell wall structure. Cellulose can be hydrolysed with enzymes back to glucose. [5] Continue reading >>

Motd Glucose

Motd Glucose

(R)-D- and (S)-L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other carbohydrates such as glucose. The reference point is the chiral center farthest from the carbonyl group. A D-carbohydrate has the same configuration at its farthest chiral center as D-glyceraldehyde (its -OH is on the right when written as a Fischer projection); an L-carbohydrate has the same configuration at its farthest chiral center as L-glyceraldehyde (its -OH is on the left). D-Glucose is the stereoisomer found in living systems. Note that the other chiral centers in D-glucose define it as a glucose and not another sugar such as mannose or galactose (different carbohydrate stereoisomers), yet only the last chiral center is relevant to defining a carbohydrate as being D or L. Most students find this definition hard to understand, so you might want to make sure you understand this before moving on. Hemiacetals are generally unstable and are only minor components of an equilibrium mixture of an aldehyde or ketone in water, except in one very important type of compound. When a hydroxyl group is part of the same molecule that contains the carbonyl group, and a five- or six-membered ring can form, the compound exists almost entirely in the cyclic hemiacetal form. Recall that five- and six-membered rings have relatively little ring strain. Carbohydrates like glucose exist in solution as cyclic hemiacetals. Because carbohydrates have several alcohol groups, they could potentially form rings of different sizes. Generally, only the most stable (strain free) cyclic structures are produced to an appreciable extent for a given carbohydrate. The new stereocenter created in a carbohydrate cyclic hemiacetal structure can have either stereochemical configuration, an Continue reading >>

Alpha And Beta Glucose Molecules - Dual View For Comparison Purposes

Alpha And Beta Glucose Molecules - Dual View For Comparison Purposes

Alpha and Beta Glucose molecules - dual view for comparison purposes Alpha and beta glucose differ only in the direction that -H and -OH groups point on carbon 1 (labelled). The description below assumes that the ring is orientated so that the movement from carbon atom C1 to C6 is in a clockwise direction. Alpha glucose has an -OH [hydroxyl] group (red sphere attached to white sphere) that points "downwards", away from the ring, whereas the -OH on carbon 1 of beta glucose is above the ring. This may be seen if the molecules are seen from the edge . Click here to move back . These two forms of glucose are (stereo)isomers, because they contain the same atoms, but they differ in the arrangement of their atoms in space. They can also be called epimers because they represent different configurations of atoms about a single stereogenic centre - in this case carbon 1. They can also be called anomers because they differ only in configuration at the hemiacetal carbon 1, also called the anomeric carbon. This difference is not enough to warrant giving these two forms different names, apart from -D-glucopyranose and -D-glucopyranose of course! This orientation is the reason for the difference between the disaccharides maltose and cellobiose .In maltose there is a (1-4) glycosidic bond formed between one -glucose and another; in cellobiose a (1-4) glycosidic bond is formed between one -glucose and another, and this has important consequences for the types of molecules which can be formed as a result of further condensation reactions. Alpha, 1-4 linkages make starch (amylose and amylopectin) fairly easily broken down by enzymes whereas beta, 1-4 linkages result in linear microfibrils of cellulose which are difficult to break down. Continue reading >>

Glucose

Glucose

This article is about the naturally occurring D-form of glucose. For the L-form, see L-Glucose. Glucose is a simple sugar with the molecular formula C6H12O6, which means that it is a molecule that is made of six carbon atoms, twelve hydrogen atoms, and six oxygen atoms. Glucose circulates in the blood of animals as blood sugar. It is made during photosynthesis from water and carbon dioxide, using energy from sunlight. It is the most important source of energy for cellular respiration. Glucose is stored as a polymer, in plants as starch and in animals as glycogen. With six carbon atoms, it is classed as a hexose, a subcategory of the monosaccharides. D-Glucose is one of the sixteen aldohexose stereoisomers. The D-isomer, D-glucose, also known as dextrose, occurs widely in nature, but the L-isomer, L-glucose, does not. Glucose can be obtained by hydrolysis of carbohydrates such as milk sugar (lactose), cane sugar (sucrose), maltose, cellulose, glycogen, etc. It is commonly commercially manufactured from cornstarch by hydrolysis via pressurized steaming at controlled pH in a jet followed by further enzymatic depolymerization.[3] In 1747, Andreas Marggraf was the first to isolate glucose.[4] Glucose is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.[5] The name glucose derives through the French from the Greek γλυκός, which means "sweet," in reference to must, the sweet, first press of grapes in the making of wine.[6][7] The suffix "-ose" is a chemical classifier, denoting a carbohydrate. Function in biology[edit] Glucose is the most widely used aldohexose in living organisms. One possible explanation for this is that glucose has a lower tendency than other aldohexoses to react nonspecific Continue reading >>

A Closer Look At Glucose

A Closer Look At Glucose

Did you know that the polymers starch and cellulose are both made by plants? In fact, plants make both starch and cellulose by connecting glucose molecules together. Every time they add a glucose to make the chain longer, a water molecule pops out! Add a glucose, out pops H2O! Add a glucose, out pops H2O! And so on and so on until the chains are really long. A starch chain can have 500 to 2 million glucose units. Cellulose can have 2,000 - 14,000 glucoses. That's a lot of sweetness! Glucose is a funny little molecule. Glucose likes to be in a ring, but sometimes the ring opens up. (Why? Why not? You can stand up, you can sit down. So sometimes you stand up!) When the ring closes again, the -OH can be pointed down, or it can be pointed out. Either way, it's still glucose! The -OH is pointed down instead of out. (We didn't draw in the C and H atoms that just hang out. See? The -OH is pointed outward instead of down. Look at the blue H atoms. They've moved around, but they're still there. (By the way, here in science land we call these molecules isomers, because they're made up of the same atoms that are put together differently.) Compare this guy to the other open chain form on the left. It's almost the same, but one of the bonds turned around, making the red O point up instead of down. Yep, it's allowed to do that! It's like swinging your arm around. Energy or Strength? Starch to store energy Plants really know how to use glucose. To make starch, they use α-glucose, with the -OH pointed down. That -OH is right where the next glucose will go. Since that one -OH is pointing down, it gives the chain a built-in curve. That curve is what makes starch so good for storing glucose. The starch polymer curls around and makes a nice little package. Many starch polymers have a lot Continue reading >>

Glucose (dextrose) - Chemistry Libretexts

Glucose (dextrose) - Chemistry Libretexts

Glucose is by far the most common carbohydrate and classified as a monosaccharide, an aldose, a hexose, and is a reducing sugar. It is also known as dextrose, because it is dextrorotatory (meaning that as an optical isomer is rotates plane polarized light to the right and also an origin for the D designation. Glucose is also called blood sugar as it circulates in the blood at a concentration of 65-110 mg/mL of blood. Glucose is initially synthesized by chlorophyll in plants using carbon dioxide from the air and sunlight as an energy source. Glucose is further converted to starch for storage. Figure \(\PageIndex{1}\):Ring Structure for Glucose Up until now we have been presenting the structure of glucose as a chain. In reality, an aqueous sugar solution contains only 0.02% of the glucose in the chain form, the majority of the structure is in the cyclic chair form. Since carbohydrates contain both alcohol and aldehyde or ketone functional groups, the straight-chain form is easily converted into the chair form - hemiacetal ring structure. Due to the tetrahedral geometry of carbons that ultimately make a 6 membered stable ring , the -OH on carbon #5 is converted into the ether linkage to close the ring with carbon #1. This makes a 6 member ring - five carbons and one oxygen. Steps in the ring closure (hemiacetal synthesis): The electrons on the alcohol oxygen are used to bond the carbon #1 to make an ether (red oxygen atom). The hydrogen (green) is transferred to the carbonyl oxygen (green) to make a new alcohol group (green). The chair structures are always written with the orientation depicted below to avoid confusion. Figure \(\PageIndex{2}\):Hemiacetal Functional Group. Carbon # 1 is now called the anomeric carbon and is the center of a hemiacetal functional group. A c Continue reading >>

Anomeric Centre (alpha And Beta)

Anomeric Centre (alpha And Beta)

This page has been approved by the Responsible Curator as essentially complete. CAZypedia is a living document, so further improvement of this page is still possible. If you would like to suggest an addition or correction, please contact the page's Responsible Curator directly by e-mail, or using this form . The anomeric centre of a sugar is a stereocentre created from the intramolecular formation of an acetal (or ketal) of a sugar hydroxyl group and an aldehyde (or ketone) group. The two stereoisomers formed from the two possible stereochemistries at the anomeric centre are called anomers. They are diastereoisomers of one another. The configuration at the anomeric centre (that derived from the carbonyl carbon) is denoted alpha- (-) or beta- (-) by reference to the stereocentre that determines the absolute configuration. In a Fischer projection, if the substituent off the anomeric centre is on the same side as the oxygen of the configurational (D- or L-) carbon, then it is the --anomer. If it is directed in the opposite direction it is the -anomer. Example 1. Fischer projections and Haworth conformational projections of L-arabinose. Example 2. Fischer projections and Haworth conformational projections of D-fructose. In the case of D-hexopyranoses drawn in the 'usual' Haworth projection, the -D-anomer is the isomer with the anomeric substituent on the opposite face to the C5 (hydroxymethyl) substitutent, ie directed down; the -D-anomer is that with the anomeric substituent being on the same face as the C5 hydroxymethyl substitutent, ie directed up. For L-hexoses the -L-anomer has the anomeric group pointing up; the -L-anomer has this group pointing down. Example 3. Fischer projections and Haworth conformational projections of D-glucose. Continue reading >>

What Is The Difference Between Alpha And Beta Glucose?

What Is The Difference Between Alpha And Beta Glucose?

-glucose) is biologically active.The mirror-image of the D-glucose , -glucose, cannot be used by cells. In solutions, the open-chain form of glucose (either 'D-' or 'L-') exists in equilibrium with several cyclic isomers, each containing a ring of carbons closed by one oxygen atom. The D-glucose can exist in two forms alpha-D-glucose and beta-D-glucose. They differ only in the direction that -H and -OH groups point on carbon 1 (See the jmol images below). When alpha-glucose molecules are joined chemically to form a polymer starch is formed. When beta-glucose molecules are joined to form a polymer cellulose is formed. Glucose 3D Molecular Structures using Jsmol Note about 3D molecules -- Our files on this page now use Jsmol instead of Jmol. These files make use of Javascript which permits viewing of molecules on tablets, phones and easier use on Macs. - Jsmol is best viewed with the Chrome browser. When a glucopyranose molecule is drawn in the Haworth projection , the designation 'a-' means that the hydroxyl group attached to C-1 and the -CH2OH group at C-5 lies on opposite sides of the ring's plane (a trans arrangement), while '-' means that they are on the same side of the plane (a cis arrangement). See below. Continue reading >>

Differences Between Alpha & Beta Glucose

Differences Between Alpha & Beta Glucose

When dissolved in water, these glucose tablets will yield a mixture of alpha and beta glucose.Photo Credit: YakubovAlim/iStock/Getty Images Based in San Diego, John Brennan has been writing about science and the environment since 2006. His articles have appeared in "Plenty," "San Diego Reader," "Santa Barbara Independent" and "East Bay Monthly." Brennan holds a Bachelor of Science in biology from the University of California, San Diego. Glucose is one of the "simple sugars" -- an ironic name, because the chemistry of these compounds is rather complex. The naming system for sugars reflects this complexity. Chemists use prefixes like alpha and beta to denote different versions of glucose and other sugar molecules. To the uninitiated, these prefixes may seem mysterious, but once you understand sugar structure, their nature and purpose will become clearer. Each molecule of glucose has a carbon backbone with -OH groups and hydrogen atoms attached to it. At the top of the chain, an oxygen atom is double-bonded to a carbon atom; collectively, these two atoms are called a carbonyl group. The carbon backbone of the glucose molecule can coil up so that an -OH group near the bottom end of the chain attacks the carbonyl carbon and the glucose molecule forms a ring. This ring-shaped structure is the cyclic form of glucose, while the straight chain structure is the linear form. In solution, the cyclic form is by far the more common. Glucose can form either five-membered or six-membered rings. The six-membered ring is much more common, and in solution the vast majority of glucose molecules are found to have six-membered rings. Since linear and cyclic forms can inter-convert, however, no glucose molecule is ever fixed in the six-membered ring form; it can go back and forth. It does sp Continue reading >>

Differences Between Alpha And Beta Glucose

Differences Between Alpha And Beta Glucose

Home / Science & Nature / Science / Chemistry / Differences Between Alpha and Beta Glucose Differences Between Alpha and Beta Glucose Glucose is the unit of carbohydrate and show the unique characteristic of the carbohydrate. Glucose is a monosaccharide and reducing sugar which is the main product of photosynthesis in plants. Chlorophylls produce glucose and oxygen using inorganic carbon and water. So, sunlight is fixed into chemical energy through glucose. Then glucose is further converted into starch and stored in plants. In respiration, glucose is broken down to ATP and provides energy to the living organisms resulting carbon dioxide and water as the final product of respiration. Glucose can be found in animals and humans, in their blood stream. Glucose is six carbon molecule or called hexose. The formula of the glucose is C6H12O6, and this formula is common to other hexoses too.Glucose can be in cyclic chair form and in chain form. Since glucose has aldehyde, ketone and alcohol functional groups it can be easily converted into straight chain form to cyclic chain form. The tetrahedral geometry of the carbons makes six membered stable ring. Hydroxyl group on the carbon five in the straight chain is linked with carbon one making hemiacetal bond (Mcmurry, 2007). So the carbon one is called anomeric carbon. When glucose is figured into fischer projection, this the hydroxyl group of the asymmetric carbon is drawn in the right and called D- glucose. If the hydroxyl group of the asymmetric carbon is in the left side in the fischer projection, it is L- glucose. D- glucose has two sterioisomers called alpha and beta differing from specific rotation. In a mixture, these two forms can be converting into each other and forms equilibrium. This process is called mutarotation. The Continue reading >>

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