< Glucose

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I put the original article here for review. It seems highly suspicious of copyright breach. After all it is a little irrevelant as well.

All life on Earth originated from certain molecules that are considered the !§building blocks of life.!¨ These molecules include lipids, proteins, nucleic acids, and carbohydrates. The last of that list, carbohydrates, are extremely important because they serve many different functions. Glucose is one of the most important carbohydrates found on the planet. It is also one of the most abundant. All life on Earth depends on glucose either directly or indirectly and it is necessary for all life. It plays many different roles both in nature and in society.

Glucose has many different forms and can be classified into many different categories. It has many different functions and plays major roles in several different fields. It is often called the most important monosaccharide because of the amount of important roles it plays. It is mainly a source of energy for cells to do work and grow. It is involved in both photosynthesis and also the human metabolism. It can be found in the human blood stream and it plays a major role in the disease diabetes. It is very important, widely used and we depend on it to survive.

Carbohydrates are classified by the number of monosaccharides, carbohydrates with three to seven carbons, they are composed of. They are grouped into three categories, monosaccharides like glucose (Figure-1), oligosaccharides like lactose (Figure-2), and polysaccharides like starch (Figure-3). Monosaccharides can then be classified again by the number of carbons then are made up with, from trioses, with three carbons, to heptoses, with seven carbons. Glucose, which has six carbons, falls into the hexose category along with other monosaccharides like fructose and galactose both of which have the same molecular formula as glucose. Besides counting the number of carbons, there are other ways of classifying monosaccharides.

One can also classify a monosaccharide by where its carbonyl group is. The difference between an aldehyde (Figure-4) and a ketone (Figure-5) group is the positioning of the carbonyl group. A carbonyl groups consists of a C=O bond within a molecule. This means that the carbon is double-bonded to the oxygen. The carbon in the carbonyl group is the first carbon in the sugar it is an aldehyde group. If the carbon of the carbonyl group is the second carbon it is a ketone group. They way that this helps with classification is that if a sugar contains a ketone group it is a ketose and if it has an aldehyde group it is an aldose. Also the ketone and aldehyde groups allow the numbering of the carbons. The first carbon is the end carbon that is closest to the double bonded oxygen. Glucose under this classification is an aldose. A major part of the classification of carbohydrates is concerning isomerism.

Isomerism occurs when two molecules have the same molecular formula yet have different structures and therefore different chemical and physical properties. There are many different kinds of isomers. There are two major divisions of isomers, geometric and structural. Structural isomers are isomers that have the same number of atoms but different arrangement of atoms. One structural isomer of glucose is fructose (Figure-6). Geometric isomers are identical with in arrangement of covalent bonds but are different in the order that the groups are arranged.

A major category is stereoisomers which are two isomers that have the number of atoms in the same order. A stereoisomer of glucose is galactose (Figure-7). In the Fischer projection all of the atoms are the same except for one rotated group. There are two categories of stereoisomers, enantiomers and diastereomers. Enantiomer are two isomers that are mirror images of each other when looked at in 3D while diastereomers are not. Galactose is just one of many diastereomers of glucose. To find out the total amount of stereoisomers a monosaccharide has one can use the formula 2x where x is the number of chiral carbons the molecule has. Chirality (Figure-8) is determined if it is a carbon with four different groups attached to it. Any carbon with a double bond on it is never chiral and the end carbons are never chiral either. Because glucose has four chiral carbons there are 24 different stereoisomers; which means that there are sixteen different stereoisomers for glucose.

Two of the main divisions of glucose!|s many forms are l-glucose and d-glucose. These two are enantiomers which are determined by whether the two molecules are symmetrical at the last chiral carbon. When the hydroxyl group is on the last chiral carbon!|s right it is considered d-glucose (Figure-9), when it is on the left it is classified as l-glucose (Figure-10). The d stands for dextro or dextrorotatory meaning right and the l stands for levo or levorotary and means left. These refer to how a plane of light rotates as it passes through a solution of it. First light is passed through a polarizing filter then a polarimeter containing a solution made with the molecule. When a d-solution is in the polarimeter it will cause the light to turn to the right or at positive angle, while an l-solution will cause the light to turn in to the left or a negative angle. Both d-glucose and l-glucose exist naturally but d-glucose, also called dextrose, is much more biologically active and much more plentiful.

Depending on where the carbonyl group alpha-d-glucose, beta-d-glucose, alpha-l-glucose, and beta-l-glucose. If the aldehyde group is arranged H-C=O then the glucose will end up in the alpha form (Figure-11) when it becomes cyclic. The conversion from straight chain to cyclic alpha-glucose, the double bond between the C and O is broken and the H from the 5th carbon leaves the hydroxyl group to join with the O. If the aldehyde is in O=C-H form it will become beta (Figure-12) when it becomes cyclic. Similar to with cyclic alpha formation the double bond between the C and O is broken and the H from the 5th carbon leaves the hydroxyl group to join with the O.

Many oligosaccharides have structures that are dependant on the structure of glucose because glucose plays a major role in the makeup of them. Glucose plays a big role especially in disaccharides, carbohydrates composed of two monomers held together by a O-glycosidic bond. O-glycosidic bonds are the bonds that connect sugars to alcohols in the form r-OH. They can be classified as either alpha or beta by the by the carbons that they connect. The naming is dependant on whether the first monomer is alpha or beta. Maltose is formed with an alpha-d-glucose and a beta-glucose and catalyzing the reaction with an enzyme. Maltose (Figure-13) can also be formed with 2 alpha-d-glucose. Glucose is also used to form lactose and sucrose. These would not exist if not for glucose.

Polysaccharides are enormously dependant on the glucose. Polysaccharides are carbohydrates that contain anywhere from nine to thousands of monosaccharides in long linear or branching chains. Starch and cellulose are both polysaccharides formed with glucose. Starch is formed with glucose molecules linked with 1,4 O-glycosidic bonds. It branches at 1,6 O-glycoside links. Because cellulose is composed of beta-glucose monomers adjacent molecules are flipped. Another polysaccharide that is formed from glucose is glycogen which is formed with alpha-d-glucoses that branch at every ten monomers.

Glucose, like other monosaccharides, can be depicted in many different ways. It can be written in its molecular formula, C6H12O6, but that is not very helpful because of the different isomers of glucose. It can also be represented as in straight-chain form. However, an even better representation than the straight-chain form is the ring or cyclic form. The ring form is much more accurate and much easier to understand. To change glucose from a straight-chain to a ring, one must go through the same synthesis reaction as either alpha or beta glucose. The C=O is broken and an H from a hydroxyl group bonds with the hydrogen.

There are two kinds of projections that can be used to view a molecule of glucose. There is the Fisher Projection which is used with the straight-chain form. With this projection all vertical bonds project back in the plane behind the paper, all horizontal bonds project out of the paper. This makes it much easier to draw and understand the molecule. Because the vertical bonds project backwards it already almost forms a ring so it is easy to understand how the straight-form could go to the cyclic form easily.

The other view is the Haworth Projection (Figure-14) which shows 3D bonds on a 2D paper. Drawing a Haworth Projection is difficult but it is a very accurate depiction of the molecule. The thick bonds in the drawing are bonds that project from the paper, the thin bonds project behind. Colors can also be employed to show which of the groups project up and which project down.

Glucose has many forms and many isomers. It has sixteen stereoisomers, a structural isomer in fructose, a diastereomer subclass and an enantiomer subclass. Glucose has two main forms, dextro-glucose, dextrose, and levo-glucose. These refer to the direction that light will turn if it is passed through a polarimeter containing a solution. From going from straight-chain to cyclic forms, glucose creates alpha and beta forms as well. This depends on the position of the carbonyl group in the molecule before the transformation. It is also an essential component in the formation of many oligosaccharides, like maltose and sucrose, and polysaccharides, like cellulose and starch. Glucose can be either represented in straight-chain form, in a Fisher Projection, in cyclic form, or in a Haworth Projection.

Glucose is an extremely important monosaccharide because it is essential for many important function in nature. It is produced by photosynthesis which is a process that converts light energy into chemical energy. Glucose can be found in blood and is the major source of energy for the cells. It is extremely plentiful in nature and can be found in both prokaryotic and eukaryotic cells. It is also a major component for other oligosaccharides and polysaccharides. It is essential for life.

The process in which glucose is created in is called photosynthesis (Figure-15). It is a process that occurs in green plants and certain other organisms that takes carbon dioxide and water to convert energy in the form of light into glucose and oxygen. All organisms need either glucose or oxygen or both to survive. Photosynthesis can be represented by the equation 6CO2 + 6H2O C6H12O6 + 6O2. Photosynthesis only occurs in organisms with chloroplast organelles within their cells. Inside the chloroplast structure is chlorophyll, the pigment that gives the plant its green color. The chloroplast is the organelle that houses the process of photosynthesis. The chloroplast is usually shaped like a disk with two membranes around it that hold the stroma. In the stroma are up to 50 granas which are stacks of thylakoids. Thylakoids are formed when two membranes join together at their end in a disk shape. Grana in a complex system of membranes called the lamelle where the chlorophyll is located. Photosynthesis is a very complicated process.

Photosynthesis is split into two different stages, light dependent reactions and light independent reactions. In the first stage, the chloroplasts collect energy from the sun!|s rays and convert it into nicotinamide adenine dinucleotide phosphate, NADPH, and adenosine triphosphate, ATP, using cellular respiration. In the second stage, the NADPH and ATP are used to build glucose molecules. NADPH donates hydrogen atoms while the ATP provides energy to synthesize glucose. Because of the number of chloroplasts in each cell, in a green plant enormous amounts are constantly being created. The plants can then use that glucose for energy. However, not all of the glucose produced in photosynthesis is used for energy. Plants also use it to create cellulose for cell walls and create starch for energy storage.

All organisms are dependent on glucose in one way or another. Glucose is the primary sugar in blood. Glucose is water soluble because of its hydroxyl groups that stick out around it. Since glucose is a source of energy, 5% mixture of D-glucose is used for IV feeding. The amount of glucose in the blood stream is regulated by the hormone insulin.

The equation for the complete combustion of glucose is C6H12O6 + 6CO2 + 32ADP + 32P 6CO2 + 6H2O + 32ATP + heat. Some cells can create 36 ATP. Several processes are involved in the complete combustion of glucose. The glucose needs to go through glycolysis, oxidative phosphorylation, Kreb!|s Cycle, and electron transport.

Glucose can be involved in metabolism in two ways, aerobic and anaerobic. The anaerobic path does not require oxygen but it is a lot less efficient in the amount of ATP that comes from a single glucose. Glycolysis, the first process that all organisms, no matter aerobic or anaerobic, is nine steps long to get from one glucose to two pyruvate and the generation of 2ATP. From there, depending on the organelles in the cell and the presence of oxygen, it can go through lactic acid fermentation, go through alcohol fermentation, or go on to oxidative phosphorylation, Kreb!|s Cycle, and electron transport and produce a total of 36ATP. The latter can only be achieved by eukaryotes and with the presence of oxygen.

Glucose is found bountifully in nature as evidenced by the following. Glucose is a monosaccharide that can be seen in ripe fruits, the nectar of flowers, leaves, honey, and saps. It has a variety of different names such as starch sugar, blood sugar, grape sugar, corn sugar, and dextrose, for dextro-glucose. Dextrose is used by cells for food. Both D and L glucose are obtained by the inversion of sucrose, which is the carbohydrate found in table sugar, and therefore are called invert sugar. Dextrose is essentially attained by the action of heat and acids on starch, and consequently also named starch sugar. Another way to form dextrose is through starchy food by the action of the ferments of saliva and pancreatic juice. D-Glucose is further biologically active and a lot more abundant than L-glucose.

Because of glucose!|s hydroxyl groups, glucose is highly hydrophilic and will attract water molecules easily. Glucose and water solutions turn into syrup when concentrated enough. On example is corn syrup which is a starch made of long glucose chains and distinctive glucose molecules. When the solution is evaporated, the glucose holds some water still behind and a syrup is formed.

There are numerous functions in nature for glucose. Going from photosynthesis in green plants to being an important component in blood it is a widely used molecule. It is an important source of energy for both prokaryotes and eukaryotes. All life on this planet is in some way dependant on glucose. One could say that it is the foundation of life. The carbohydrate glucose is very important for life on this planet. Glucose in the Industrial and Medical World

Glucose is not only immensely important in nature but also in the medical and commercial communities. In the medical world it, because it is blood sugar, has a lot to do with the disease diabetes which affects a large number of people worldwide. It also has large manufacturing purposes in the food industry.

Glucose plays a major role in the disease diabetes mellitus. There are other forms of diabetes, including diabetes insipidus and diabetes inositus but these have less to do with glucose and are not as common as diabetes mellitus. Because of this, the term !§diabetes!¨ always refers to the disease diabetes mellitus. When a human eats food, enzymes in his body break down the majority of the food into glucose and other carbohydrates. The glucose molecules are then sent into the bloodstream to be used by cells for energy. To help make the path ways for the glucose, the hormone insulin is release. Insulin attaches to the cells and clears a pathway for the glucose. Insulin helps regulate the blood sugar concentration.

Diabetes mellitus occurs when either pancreatic islet cells are not creating enough insulin to regulate the blood sugar level or when the cell cannot use the insulin effectively. Normally the insulin would be produced in the pancreas to enable the cells to use the glucose. It allows the glucose to move from the blood to the cells where it can be used for energy and growth. In muscle and liver cells, the insulin facilitates the storage of glucose in the form of glycogen. In adipose tissue, insulin helps with change the glucose to fat, triglycerides, and the storage of the recently produced triglyceride inside the fat cells. It also contributes to allowing the amino acids into cells and simulates protein combination. If the body either cannot use the insulin or is not producing enough of it, it is a condition called diabetes mellitus. People with diabetes mellitus have extremely high blood sugar levels.

With diabetes mellitus, glucose is immersed in the bloodstream as it can not enter the cells. The lack of insulin prevents it from being used normally for energy. There is a lot of excess glucose in the body which builds up in the bloodstream. This results in a condition known as hyperglycemia. The excess amount of glucose passes out of the body in the urine. Because the liver changes amino acids in to glucose, this leads to extra losses of glucose, water, and electrolytes through the urine and may wreck the water balance and acid-base balance.

When blood passes through the kidneys, which remove blood impurities, it cannot absorb all of the excess glucose. This extra glucose goes into the urine and brings water and electrolytes with it. This leads to more frequent urination and dehydration. People suffering from diabetes mellitus experience excessive thirst and hunger to replace the lost water and glucose. Other symptoms include blurred vision, dramatic weight loss, irritability, weakness and fatigue, and nausea and vomiting. Also because people with diabetes can not use glucose, their bodies begin to break down fats that were stored for fuel. This causes excess amounts of acidic components called ketone bodies in the blood which will interfere with respiration.

Diabetes is considered an autoimmune disease because it causes the immune system to attack and destroy beta cells within the pancreas which produce insulin. Many scientists believe that the disease is caused by genetic and environmental factors. Diabetes also may develop if the muscle and fat cells within respond poorly to insulin. Within the US, there are approximately 16 million people suffering from diabetes though only about half have been diagnosed. 650,000 people every year learn that they have diabetes mellitus. It is the 7th leading cause of death and the 6th leading cause of all deaths caused by disease. It is most prominent in adults 45 years and older, people overweight or not physically active, people with a family history of diabetes mellitus, and in minority groups including African Americans, Hispanics, and the highest in Native Americans. Diabetes is found generally more frequently in women than in men.

There are two major types of diabetes mellitus, Type I, previously discussed, and Type II or non-insulin-dependent diabetes mellitus (NIDDM). Type II is much more common than Type I; 90% to 95% of all people with diabetes have Type II. In Type II the cells do produce insulin however it either is not enough or it does not work properly. The symptoms to of Type II are similar to those of Type I. Detection of diabetes comes from looking at the amount of glucose in the blood over a time of when the individuals have fasted for several hours. One test for Type I that is currently being developed looks for specific antibodies and proteins in the immune system. The treatment for diabetes once it is diagnosed consists of regulating the amount of glucose in the blood and preventing complications. This is accomplished through a combination of regular exercise, a careful diet, and medication.

People who have the Type I version of this disease require constant insulin injections around two to four times each day. This is to compensate for the amount of insulin that is not produced by the body. People with Type I diabetes also must careful with their meals and distribute their sugar intake throughout the day so as not to overwhelm there insulin supply. It is better for them to eat more complex carbohydrates which take longer to break down and therefore cause a slower rise in blood sugar level. People with Type II diabetes require diet control, weight reduction, and exercise. People who suffer from diabetes may be prescribed an oral sugar lowering agent if they do not require insulin or if they have trouble giving themselves injections.

Both the process of making bread (Figure 16) and of making beer (Figure 17) involves glucose. They both are involved in a process called alcohol fermentation. In both cases starch from a grain is converted in to glucose which then goes through glycolysis inside of yeast living in there. Since yeast is anaerobic when O2 is not readily available it goes in to alcohol fermentation with the resulting two pyruvate. In this process the pyruvate decarboxylase changes the pyruvate in to acetaldehyde and releases CO2. Then ethanol dehydrogenase changes it into ethyl alcohol. In the case of bread, the CO2 creates air bubbles in the dough and causes it to !§rise.!¨ Then since it is porous, the alcohol evaporates into the air. In beer, since the container is airtight, the pressure forces the CO2 to dissolve in the liquid. Also since it is air tight, the alcohol remains.

Glucose is found also in many of the foods we eat, in tanning products, dye baths, skin treatment medicines, and many other products. One of the things that glucose plays a major role in is syrup. When a glucose solution is evaporated the glucose holds some water behind. A bacterium, aspergillus oryzae, is used by industry to make corn syrup because of its ability to break down starch molecules. This process of creating syrup is used for the manufacture of hard candy. When sugar and water are boiled down and cooled, the solution becomes a hard, transparent, form. Fructose is made from glucose in corn syrup with streptomyces bacteria, which rearranges the atoms of glucose into fructose.

Glucose is clearly very important in both medicine and industry. Regulation of it within the blood is the key to the disease diabetes. Diabetes is a disease that affects so many people worldwide that it is hard to not see its effects. It is a very important aspect to manufacturing industries which use it to make many products. Products that contain it range from skin care to the food that we eat. It has a very important purpose within our lives both naturally and artificially.

Glucose is a very important carbohydrate, with many forms and functions. It is useful for not only humans but also for animal, plants and essentially every other organism on the planet. It has 16 different stereoisomers and comes in a wide variety of forms. It is a major component of many different oligosaccharides and polysaccharides. It is fuel for our cells and it travels in our blood. Glucose is closely linked to diabetes, the seventh leading killer in the world. It is essential for our foods like bread and beer. It can be found in fruits and plants. Glucose is important to the medical world, the industrial world, the natural world, and especially our world. Glucose truly is a very useful carbohydrate.