Notes and Practice Problems

The chemical formula for a simple sugar is C x (H 2 O) y, where x is at least 3. A sugar with 3 carbons is called a TRIOSE, 4 sugars is a TETROSE, 5 is a PENTOSE. In this class, we will focus on the six carbon basic unit for sugars, the Hexoses.

The general formula of a six carbon carbohydrate is C 6 H 12 O 6 Notice that the ratio of the atoms is a 1:2:1 ratio. Monosaccharides (from the Greek monos: single, sacchar: sugar) are the simplest carbohydrates. They cannot be broken down into simpler sugars.

Monosaccharides are also known as the simple sugars. Monosaccharides are also known as the simple sugars. Mono means ONE, saccharide means sugar. All of the monosaccharides listed in the next slide are isomers of each other. What does this mean? What is the famous name of a sugar substitute found in some diet beverages? (Sounds like saccharide)

C 6 H 12 O 6 is the molecular formula for many different monosaccharides. Some of these include: Glucose: blood sugar Fructose: fruit sugar Manose: used to treat bacterial infections, found in some fruits such as cranberry. Galactose: a nutritive sweetener (food additive)

Sucrose is composed of glucose and fructose. Disaccharides are sugars that are composed of two individual sugars that have combined to make one larger sugar. Sucrose and lactose are probably the most famous examples of this type of sugar. Sucrose is composed of glucose and fructose. Lactose is composed of glucose and galactose. The molecular formula for sucrose and other disaccharides is C 12 H 22 O 11. Does this have the formula of a carbohydrate?

The answer is yes. The reason being is this; if you combine the two molecular formulas you get C 6 H 12 O 6 glucose C 6 H 12 O 6 fructose C 12 H 24 O 12 Every time you combine sugars, you lose one molecule of water in the process. However, in order for carbon compounds to combine, they must lose something off of the carbons to make room. One sugar loses an H and the other loses an OH. Together that makes a water. So the rule is this: Every time you combine sugars, you lose one molecule of water in the process.

Glucose Molecule Fructose Molecule

Notice in the previous slide that Sucrose is composed of two different sugars. This does not mean that it will be twice as sweet. If you continue to add sugars together you will get complex carbohydrates, like starches. Breads, potatoes, pastas, things like that are made up of sugars, and they are not sweet. In class I showed you a demo that indicated that sucrose was composed of GLUCOSE and something else. It was AT LEAST glucose plus another substance as it DID NOT react to Benedict’s solution.

 Notice that sucrose is composed of glucose and fructose COMBINED. There is a chemical test for the monosaccharide glucose. It is called the Benedict’s test.

To prove that sugars contain C,H, and O the simplest thing to do is to gently heat the sugar in a test tube. The initial heating will cause a phase change from solid to liquid. Tasting the sugar will demonstrate that it has not changed into new matter since it will still have a sweet taste.

 Intense heating will break bonds and cause the molecules to break down into carbon and water vapor. When large molecules are broken down into smaller molecules, the process is called catabolism. Water contains hydrogen and oxygen. Carbon remains. This is proof that sugars contain these three types of atoms.

Anabolism would be the reverse process. If catabolism is the breaking down of molecules, anabolism is the building up of molecules. An example of this would be photosynthesis. Plants combine water and carbon dioxide to make sugars.

If you add Benedict’s solution to Sucrose, you will get NO REACTION as sucrose is a different compound than glucose. It is made glucose and fructose combine, but remember that when atoms and molecules combine with other things they take on completely different properties.

Here you can see the results of glucose and Benedict’s Solution. If there is no reaction, the solution remains light blue. It then progresses to the dark (I will call it orange) for a lot of glucose.

If Benedict’s solution is added to the monosaccharide, glucose and heated gently, it will react. If a solution of HCl is added to sucrose, sucrose will split into glucose and fructose and will then react to Benedicts, showing that it is a disaccharide. This is significant as it is showing that large molecules can be broken down into smaller molecules (catabolism).

A chemical test for Fructose is the Seliwanoff Test. a solution suspected of containing Fructose is mixed with Seliwanoff’s Solution. A positive test is a red which is shown below.

Another common disaccharide is Lactose, or milk sugar. This sugar is produced when a glucose and a galactose molecule are joined. Lactose is the sugar that is converted into an acid by bacteria. The result is sour milk.

What would be the molecular formula if 3 monosaccharides were combined?/11

always one less water than the number of sugars Notice that with a carbohydrate, the Hydrogen is always double the number of oxygen atoms. A monosaccharide has the molecular formula of C 6 H 12 O 6. Multiplying each times 3 gives you C 18 H 36 O 18. Subtract two molecules of water (always one less water than the number of sugars) means you lose 4-H and 2-O. The new formula is C 18 H 32 O 16. Notice that with a carbohydrate, the Hydrogen is always double the number of oxygen atoms.

What would be the molecular formula if two disaccharides were combined to make one polysaccharide?

There are two possible ways to do this problem: 1. You can multiply a monosaccharide by 4 and then subtract 3 molecules of water; or 2. You can add two disaccharides together and then subtract 1 water. The reason only one water is subtracted using this method is that you have already lost two hydrogens with the two disaccharides forming. Either way the formula is C 24 H 42 O 21.

How many monosaccharides were combined to make the complex carbohydrate? C 72 H 122 O 61

Monosaccharides contain 6 carbon atoms, so divide the number of carbons by 6. The smallest carbohydrate is a monosaccharide. Monosaccharides contain 6 carbon atoms, so divide the number of carbons by 6. 72/6 = 12 monosaccharides

A complex carbohydrate is converted into monosaccharides. If 9 water molecules were used to do this, what was the molecular formula of the carbohydrate?

The main concept with this problem involves the relationship between combining sugars and the number of waters that are lost.Every sugar to sugar bond created will result in the loss of one molecule of water. The main concept with this problem involves the relationship between combining sugars and the number of waters that are lost. Every sugar to sugar bond created will result in the loss of one molecule of water. There will always be one less water lost than the number of sugars. If 9 waters are lost then 10 monosaccharides were combined. 10 x C 6 H 12 O 6 = C 60 H 120 O 60 Now subtract the 9 waters = -18 H and -9 O to give C 60 H 102 O 51

Notice that the “sucralose” is actually NOT a sugar despite the ending “OSE”. It contains 3 Chlorine atoms as well as other carbon groups.

The question that always comes up is, “What is better for you, sugar in a coke or the artificial sweetener?” Actually, the best answer is that you should probably be drinking WATER. People who stop drinking a sugared coke each day, lose, on average, 10 pounds a year. The reason is that a single coke has as many calories as a candy bar.

Actually, your carbonated beverages do NOT contain sugar, Sucrose. Now they are sweetened with an artificial substance, HFCS, high fructose corn syrup. This is a blend of glucose and fructose (52% glucose and 48% fructose). HFCS has been linked to the following: Increased diabetes, obesity, insulin resistance, Metabolic Syndrome (this is a combination of disorders that increase the risk of Cardiovascular Disease).

The delusion that fructose is an acceptable form of sugar is quite prevalent in many nutritional circles. In fact, nearly all simple sugars are metabolized quickly and disrupt insulin levels, which contributes to most chronic illness. Eating small amounts of whole fruit will not provide tremendous amounts of fructose and should not be a problem for most people, unless diabetes or obesity is an issue but fruit juices, sodas and other beverages sweetened with fructose should be avoided.-From Organic Consumers

Fructose has potentially harmful effects on other aspects of metabolism. In particular, fructose is a potent reducing sugar that promotes the formation of toxic advanced glycation end-products, which appear to play a role in the aging process; in the pathogenesis of the vascular, renal, and ocular complications of diabetes; and in the development of atherosclerosis. Fructose has also been implicated as the main cause of symptoms in some patients with chronic diarrhea or other functional bowel disturbances. In addition, excessive fructose consumption may be responsible in part for the increasing prevalence of obesity, diabetes mellitus, and non-alcoholic fatty liver disease. – Taken from PubMed.gov Abstract Adverse Effects of Dietary Fructose

A study from Princeton published in the February issue of the journal Pharmacology, Biochemistry and Behavior (PDF) shows that high fructose corn syrup (HFCS), used as a cheap sweetener in everything from Coke to Progresso soup, is not the same as table sugar, namely for the way that it makes you gain 48% more weight.published in the February issue of the journal Pharmacology, Biochemistry and Behavior

 Some people have claimed that high-fructose corn syrup is no different than other sweeteners when it comes to weight gain and obesity, but our results make it clear that this just isn't true, at least under the conditions of our tests," said psychology professor Bart Hoebel. "When rats are drinking high- fructose corn syrup at levels well below those in soda pop, they're becoming obese — every single one, across the board. Even when rats are fed a high- fat diet, you don't see this; they don't all gain extra weight."  Since HFCS was introduced into the American food supply as a cost- effective sweetener, the population's obesity rate has shot up from 15% in 1970 to nearly 33% today.-published in the February issue of the journal Pharmacology, Biochemistry and Behaviorpublished in the February issue of the journal Pharmacology, Biochemistry and Behavior

The artificial sweetener aspartame has been the subject of several controversies. Aspartame has been found to be safe for human consumption by more than ninety countries worldwide, [12][13] with FDA officials describing aspartame as "one of the most thoroughly tested and studied food additives the agency has ever approved" and its safety as "clear cut". [4] The weight of existing scientific evidence indicates that aspartame is safe as a non-nutritive sweetener.artificial sweeteneraspartame [12][13] [4]

Claims that numerous health risks (such as multiple sclerosis, systemic lupus, methanol toxicity, blindness, spasms, shooting pains, seizures, headaches, depression, anxiety, memory loss, birth defects and death [6] ) are associated with the consumption of aspartame in normal doses. These health risk claims have been examined and debunked by numerous scientific research projects, and are also generally dismissed by governments and major health and food safety organizations. [6] "Food Additive Approval Process Followed for Aspartame""Food Additive Approval Process Followed for Aspartame". Food Additive Approval Process Followed for Aspartame GAO/HRD United States General Accounting Office. June 18, Additive Approval Process Followed for Aspartame GAO/HRD-87-46http:// Aspartame: A Safety Evaluation Based on Current Use Levels, Regulations, and Toxicological and Epidemiological Studies". Critical Reviews in Toxicology 37 (8): 629–727.

Sucralose is one of the five FDA-approved non- nutritive sweeteners which has more recently become an important constituent of numerous processed foods. In fact, it is found in around 4,500 food and beverage products in the world of late. Sucralose is approximately 600 times as sweet as sucrose (table sugar), twice as sweet as saccharin, and 3.3 times as sweet as aspartame.sweet sucrosesaccharinaspartame

Splenda, the brand name for sugar-derivative sucralose, is converted from cane sugar to a no-calorie sweetener. It isn’t recognized as sugar by the body and therefore is not metabolized. Splenda is marketed as a “healthful” and “natural” product since it is derived from sugar. However, its chemical structure is very different from that of sugar and sucralose is actually a chemical substance.

Despite the manufacturer’s claims to the contrary, sucralose is significantly absorbed and metabolized by the body. According to the FDA’s “Final Rule” report, 11% to 27% of sucralose is absorbed in humans, and the rest is excreted unchanged in feces. According to the Japanese Food Sanitation Council, as much as 40% of ingested sucralose is absorbed. Some chlorinated molecules serve as the basis for pesticides such as D.D.T., and accumulate in body fat.

The chlorocarbons have long been known for causing organ, genetic, and reproductive damage. It should be no surprise, therefore, that the testing of sucralose reveals that it can cause up to 40 percent shrinkage of the thymus: a gland that is the very foundation of our immune system. Sucralose also causes swelling of the liver and kidneys, and calcification of the kidney.

 Research in animals has shown that sucralose can cause many problems such as:  · Shrunken thymus glands (up to 40 percent shrinkage)  · Enlarged liver and kidneys  · Atrophy of lymph follicles in the spleen and thymus  · Increased cecal weight  · Reduced growth rate  · Decreased red blood cell count  · Hyperplasia of the pelvis  · Extension of the pregnancy period  · Aborted pregnancy  · Decreased fetal body weights and placental weights  · Diarrhea

Saccharin has been around for over 100 years and claims to be the "best researched sweetener.” It does not contain any calories, does not raise blood sugar levels, and its sweetness is 200 to 700 times sweeter than sucrose (table sugar). It has a bitter aftertaste. In 1977, research showed bladder tumors in male rats with the ingestion of saccharin and the FDA proposed a ban on saccharin.

Congress intervened after public opposition to the ban. This was the only artificial sweetener available at that time and the public did not want to lose the diet products that contained it. Since then, more than 30 human studies have been completed and found that the results found in rats did not translate to humans, making saccharin safe for human consumption. The reason for this may be that the original study gave the rats an amount that was hundreds of times higher than "normal" ingestion for humans.

Aside from being implicated with potential cancers, another possible danger of saccharin is the possibility of allergic reactions. Reactions can include headaches, breathing difficulties, skin eruptions, and diarrhea. It's also believed that the saccharin found in some infant formulas can cause irritability and muscle dysfunction. For these reasons, many people still believe that the use of saccharin should be limited in infants, children, and pregnant women.

Keep in mind research is always ongoing and information constantly changes. Be an informed consumer, look up information, and make your decisions based upon fact. Then, go get a glass of water.

Here you can see the effects of heating a test tube of sugar. Aside from the smoke, water vapor forms as well as carbon. This proves the following: NEXT SLIDE

1. Both Glucose and Sucrose contain Carbon, Hydrogen, and Oxygen since Carbon and water are produced. 2. Catabolism takes place. Large sugar molecules are broken down into Carbon and Water. 3. Sugar is a compound. It has different properties than the Carbon and Water that comprise it. 4. Sugar changes properties when it has water removed. This creates new matter. 5. When you initially heat the sugar, gently, you melt it. This is a PHASE CHANGE. When you tasted the sugar, it should have tasted the same as no new matter is created.

Notice in this photo that tubes 1-3 are still blue. This means no glucose. These tubes had sucrose, base, and fructose. Tube 4 is an orange/brown color. This means that GLUCOSE is present. Tube 5 is a positive test for FRUCTOSE using the Seliwanoff Reagent.

In this photo you can see the positive test for FRUCTOSE. In the tube on the left, a known sample of Fructose was reacted with Seliwanoff’s Reagent. The tube on the right was the split sucrose, indicating Fructose is present.

This photo shows what you should have had for your results. Tubes 1-3 show that heat, water, chemicals, and Benedicts do not react. Only when sucrose is split, in tube 4, do you get a positive test for Glucose.

Here you can see everything. Positive test for Fructose in tube 1 and 6. No glucose in tubes 2-4, and in the 5 th tube, a positive test for Glucose. This proves Sucrose is AT LEAST a Disaccharide, since two sugars were identified.

So, in summary, a positive test for Glucose is that when mixed with Benedict’s Solution, a color change occurs. Depending on the amount of glucose, the color will vary.