Milbank High School
 1.What are carbohydrates? What is the difference
between mono-, di-, and polysaccharides?
 2.What are the structures of the most commonly
occurring monosaccharides? Be able to classify
them as aldoses or ketoses and as trioses, pentoses,
or hexoses.
 3.What is the difference between a D and an L
sugar?
 4.What is mutarotation? How does it occur?
 5.What are the structures of sucrose, lactose, and
maltose, the most common disaccharides? What
monosaccharides make up each of these
disaccharides?
 6.Compare and contrast starch, glycogen, and
cellulose.
 the chemistry of molecules and
reactions found in living organisms
 “Carbon hydrates”
 Compounds containing carbon, hydrogen, and
oxygen
 Starches and fibers (complex carbohydrates)
 Sugars
 Cellulose
 Contain hydroxyl groups
 And either an aldehyde or ketone
 Known as polyhydroxy aldehydes or ketones
 Simple carbohydrates
 Cannot be further hydrolyzed
 Contain 3-7 carbons
 Readily dissolve in water
 Can link together to form more complex carbohydrates
 Disaccharides
 Trisaccharides
 Polysaccharides
 Named using IUPAC to name monosaccarides
 Name the number of carbons, then add
 Trios, tetrose, pentose, hexose etc
 If aldehyde is attached: aldotetrose
 If ketone is attached: ketotetrose
-ose
 Glucose
 Fructose
 Molecules that are nonsuperimposable mirror images
of each other
 Have identical physical properties except one:
 They rotate plane-polarized light in opposite directions
 Simplest sugars
 Two enantiomers
sugars
L sugars
 D

 Aldohexoses
 16 isomers (8 enantiomeric pairs)
 3 most common:
 Glucose, mannose, galactose
 Ketohexoses
 8 isomers
 fructose
 Most abundant sugar in nature
 Fruits
 “grape sugar”
 “Dextrose” b/c it is dextrorotatory
 Carbs converted to glucose
 Produces energy for our cells
 Circulating carbohydrate
 Blood sugar
 Synthetically made by the hydrolysis of starch
 Corn starch
 “corn sugar”
 Component of polysaccharide mannan
 Berries
 Vegetable ivory “endosperm”
 Differs from glucose at only one point
 Needed by human body for synthesis of lactose
 In mammary glands
 Also important constituent of the glycolipids
 Occur in brain in myelin sheath of nerve cells
 “brain sugar”
 Differs from glucose at only one point
 Only naturally occurring ketohexose
 Also similar structure to that of glucose
 Found in honey (40%)
 Formed in prostate gland
 Energy source for spermatozoa
 High-intensity sweeteners
 Manufactured in place of mono- and disaccharides
 Saccharin
 1890’s
 500-700 times sweeter than sucrose
 Carcinogenic
 Aspartame
 1967
 160 times sweeter than sucrose
 Used in diet soda
 Sucralose
 1998
 600 times sweeter than sucrose
 Passes through body unchanged
 Crystalline solids at room temperature
 Quite soluble in water
 Converted to anions when Tollen’s and Benedict’s
reagents are used
 Used in simple and rapid diagnostic tests for the
presence of glucose in blood or urine
 Composed of two monosaccharide units
 Joined when one monosaccharide reacts with the
hydroxyl group of a second monosaccharide
 Forms a carbon-oxygen-carbon linkage
 “glycosidic linkage”
 Occurs in sprouting grain
 Forms “malt” in the manufacture of beer
 “malt sugar”
 About 30% as sweet as sucrose
 Body can’t utilize it directly
 Must be broken down by enzymes
 “Milk sugar”
 Occurs in the milk of humans, cows, and other





mammals
Human milk: 7.5% lactose
Cow’s milk: 4.5% lactose
Synthesized only by mammary tissue in nature
Commercial produced from whey (from cheese)
1/6th as sweet as sucrose
 People are unable to digest lactose in milk
 Need lactase in small intestine to digest it properly
 Up to 20% of US population suffer some degree of
lactose intolerance
 Produces bacteria in colon if not broken down
properly
 Leads to abdominal distension, cramps, diarrhea
 Foods can be treated with lactase
 Lactacid®
 Tablets taken orally with dairy foods to assist in their
digestion
 “Beet sugar, cane sugar, table sugar, or just sugar”
 Largest selling pure organic compound in the world
 Obtained from sugar canes and beets
 Average American: 100 pounds of sucrose every year
 May cause cancer, heart disease, migraine headaches,
hyperactivity in children, obesity, and tooth decay
 Most abundant carbs in nature
 Store energy and make up plant cells
 High-molar mass
 Starch, glycogen, and cellulose
 Most important source of carbs in the human diet
 More than 50% of our carb intake
 Granule form
 Storage
 Potatoes: 15%
 Wheat: 55%
 Corn: 65%
 Rice: 75%
 Mixture of amylose and amylopectin
 Amylose: 60-300 glucose units per chain
 Amylopectin: 300-6000 glucose units
 Commercial starch
 White powder
 Stamps, envelopes, labels (sticky upon wetting)
 “animal starch”
 Reserve carb of animals
 All mammalian cells contain glycogen
 Liver and skeletal cells the most
 Used when fasting
 Fibrous carb found in all plants
 Cell walls
 Most abundant of all carbs
 Makes up 50% of all carbon in the vegetable world
 Much hydrogen bonding…insoluble in water
 Can’t be digested by humans
 Herbivores contain special enzymes to digest it and
use it for energy
 Termites
 Insoluble fiber (cellulose)
 Reduces risk of colon cancer and heart disease
(reduces cholesterol)
 ADA recommends 20-35 g a day
 Most Americans get 14-15 g a day