Organic Chemistry Questionnaire

You must use structural formulas not molecular ones for the following reactions:

a) Write a reaction for formation of triacylglycerol with linoleic acid, palmitoleic acid and lauric acid

b) Write a hydrogenation reaction for glyceryl trilaurate.

Chapter 13 Carbohydrates
Paula, a diabetes nurse,
teaches Kate to test her blood
glucose levels before and after
a meal.
Paula explains to her that her
pre-meal number should be
110 mg/dL or less, and if it
increases by more than
50 mg/dL, she needs to lower
the amount of carbohydrates
she consumes.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chapter 13 Readiness
Core Chemistry Skills
• Identifying Functional Groups (12.1)
• Naming Alcohols and Phenols (12.1)
• Naming Aldehydes and Ketones (12.3)
• Writing Equations for the Dehydration and Oxidation of
Alcohols (12.4)
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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13.1 Carbohydrates
Carbohydrates are
• a major source of energy from
our diet
• made from the elements carbon,
hydrogen, and oxygen
• also called saccharides, which
means “sugars”
Learning Goal Classify a monosaccharide as an aldose or a
ketose, and indicate the number of carbon atoms.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Types of Carbohydrates
The types of carbohydrates are
• monosaccharides, the simplest carbohydrates
• disaccharides, which consist of two monosaccharides
• polysaccharides, which contain many monosaccharides
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Monosaccharides
Monosaccharides
• consist of three to eight carbon
chains with one carbon in a
carbonyl group
• containing an aldehyde group
are classified as an aldoses
• containing a ketone group are
classified as a ketoses
• have hydroxyl groups on all
carbons except the carbonyl
carbon
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Types of Monosaccharides
Monosaccharides are also classified by the number of carbon
atoms present.
triose (three C atoms)
tetrose (four C atoms)
pentose (five C atoms)
hexose (six C atoms)
An aldopentose is a five-carbon saccharide with an aldehyde
group.
A ketohexose is a six-carbon saccharide with a ketone group.
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Types of Monosaccharides
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Study Check
Identify each as aldo or keto and as tetrose, pentose, or hexose.
A.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
B.
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Solution
Identify each as aldo or keto and as tetrose, pentose, or hexose.
A. aldohexose
B. ketopentose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Structural Isomers
Molecules are structural isomers when they have the same
molecular formula but different bonding arrangements.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Stereoisomers
Stereoisomers have identical molecular formulas
• and are not structural isomers
• with atoms bonded in the same sequence but differ in the way
they are arranged in space
When the mirror images of organic molecules cannot be
completely matched, they are
• nonsuperimposable
• chiral (pronunciation ‘kai-rel)
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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13.2 Chiral Molecules
Left and right hands are chiral because they have mirror
images that cannot be superimposed on each other.
Learning Goal Identify chiral and achiral carbon atoms in
an organic molecule.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chirality
Chiral molecules have
• the same number of atoms
but are arranged differently in space
• a nonsuperimposable mirror image
Hands are like chiral molecules—they are
mirror images and cannot be superimposed.
When the mirror images of molecules are
identical and superimposable, the molecules
are achiral.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Everyday Objects, Chiral and Achiral
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chiral Carbon Atoms
Molecules are chiral when they have
• at least one or more chiral carbon atoms
• a carbon atom, bonded to four different groups
• nonsuperimposable mirror images
Core Chemistry Skill Identifying Chiral Molecules
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chiral Carbon Atoms
• The mirror image of a chiral compound cannot be
superimposed.
• When stereoisomers cannot be superimposed, they are
called enantiomers.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Achiral Carbon Atoms
When the mirror image of an achiral structure is rotated, and
the structures can be aligned with each other, their mirror
images are said to be superimposable.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Identify each as a chiral or an achiral compound.
Cl
Cl
H
C
CH3
CH2CH3
A.
H
C
Cl
CH3
H
C
H
Br
B.
C.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
CH3
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Solution
Identify each as a chiral or an achiral compound.
Cl
Cl
H
C
CH3
H
C
Cl
CH3
H
C
CH3
H
Br
A.
B.
C.
chiral
achiral
chiral
CH2CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Drawing Fischer Projections
A Fischer projection
• is a two-dimensional representation of a three-dimensional
molecule
• places the most highly oxidized carbon group at the top
• uses vertical lines in place of dashes for bonds that go back
• uses horizontal lines in place of wedges for bonds that
come forward
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Chiral Carbon, Fischer Projections
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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D and L Notations
D or L isomers are assigned according to the position of the
— OH group on the chiral carbon farthest from the carbonyl
carbon.
• The letter L is assigned to the structure with the — OH on
the left.
• The letter D is assigned to the structure with the — OH on
the right.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Indicate whether each pair is a mirror image that cannot be
superimposed (enantiomers).
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Indicate whether each pair is a mirror image that cannot be
superimposed (enantiomers).
Yes
No
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Identify the following Fischer projections of aldose as L or
D isomers:
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Identify the following Fischer projections of aldose as L or
D isomers:
D-Isomer;
L-Isomer;
— OH is on the right.
— OH is on the left.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Enantiomers in Biological Systems
Many compounds in biological systems have only one
enantiomer that is active. This happens because
• the enzymes and cell surface receptors on which metabolic
reactions take place are themselves chiral
• only one enantiomer interacts with its enzymes or receptors;
the other is inactive
• the chiral receptor fits the arrangement of the substituents in
only one enantiomer; its mirror image does not fit properly
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Enantiomers in Biological Systems
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Enantiomers in Biological Systems
• A substance used to treat Parkinson’s disease is L-dopa,
which is converted to dopamine in the brain, where it raises
the serotonin level.
• The enantiomer, D-dopa, is not effective for the treatment of
Parkinson’s disease.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Enantiomers in Biological Systems
• For many drugs, only one of the enantiomers is
biologically active.
• However, for many years, drugs have been produced that
were mixtures of their enantiomers.
• Today, drug researchers are using chiral technology to
produce the active enantiomers of chiral drugs.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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13.3 Fischer Projections of
Monosaccharides
Glucose, galactose, and fructose are the most important
monosaccharides.
Learning Goal Use Fischer projections to draw the
D or L stereoisomers of glucose, galactose, and fructose.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Fischer Projections
A Fischer projection used to represent carbohydrates
• places the most oxidized group at the top
• shows chiral carbons as the intersection of vertical and
horizontal lines
• shows the — H and — OH groups on the horizontal
intersecting line
• places the — CH2OH group at the bottom of the Fischer
projection, which is not chiral
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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D and L Notations
In a Fischer projection, the — OH group on the
• chiral carbon farthest from the carbonyl group determines
an L or D isomer
• left is assigned the letter L
• right is assigned the letter D
Core Chemistry Skill Identifying D- and L-Fischer
Projections
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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D and L Isomers of Monosaccharides
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
In the following Fischer projection of mannose, identify the
monosaccharide as a D or an L isomer.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
In the following Fischer projection of mannose, identify the
monosaccharide as a D or an L isomer.
Need to Identify
Carbon Chain
ANALYZE
THE
PROBLEM
Procedure
Number the carbon chain,
starting at the top of the
Fischer projection.
Chiral Carbon
Chiral carbon 5 has the
highest number.
Position of — OH The — OH group is drawn
on the right side of carbon
5, which makes it D-mannose.
Mirror Image
The — OH groups on the
chiral carbons are drawn on
the opposite side.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
In the following Fischer projection of mannose, identify the
monosaccharide as a D or an L isomer.
D-Mannose; the
— OH on
carbon 5 is on the right.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
In the following Fischer projection,
A. identify the number of chiral centers.
B. identify the monosaccharide as a D or an L isomer.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
In the following Fischer projection,
A. identify the number of chiral centers.
B. identify the monosaccharide as a D or an L isomer.
two chiral centers
— OH is on the left;
it is an L isomer.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Glucose and Fructose
D-Glucose is
• found in fruits, corn syrup, and honey
• an aldohexose with the formula C6H12O6
• known as dextrose and blood sugar in the body
• a building block in sucrose, lactose, maltose, and in
polysaccharides such as cellulose and glycogen
D-Fructose, obtained from sucrose, is
• a ketohexose with the formula C6H12O6
• the sweetest of the carbohydrates, twice as sweet as sucrose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Glucose and Fructose
The sweet taste of honey
comes from the
monosaccharides
D-glucose and D-fructose.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Galactose
D-Galactose
• is an aldohexose, C6H12O6
• is not found free in nature
• is obtained from the disaccharide lactose
• has a similar structure to glucose except
for the — OH on carbon 4
In a condition called galactosemia, an
enzyme needed to convert galactose to
glucose is missing.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Hyperglycemia and Hypoglycemia
In the body,
• glucose has a normal blood level of 70–90 mg/dL
• a glucose tolerance test measures blood glucose for several
hours after ingesting glucose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Hyperglycemia and Hypoglycemia
Diabetes mellitus can cause hyperglycemia, which
• occurs when the pancreas is unable to produce sufficient
quantities of insulin
• allows glucose levels in the body fluids to rise as high as
350 mg/dL of plasma
Symptoms of diabetes include
• thirst and excessive urination
• increased appetite and weight loss
In older adults, diabetes is sometimes a consequence of excessive
weight gain.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Hyperglycemia and Hypoglycemia
When a person is hypoglycemic,
• the blood glucose level rises and then decreases rapidly to
levels as low as 40 mg/dL
• low blood sugar may occur as a result of an overproduction of
insulin by the pancreas
• symptoms may appear, such as dizziness, general weakness,
and muscle tremors
• a diet may be prescribed that consists of several small meals
high in protein and low in carbohydrates
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Draw the Fischer projections of D-fructose and L-fructose.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Draw the Fischer projections of D-fructose and L-fructose.
D-Fructose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
L-Fructose
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13.4 Haworth Structures of
Monosaccharides
• The most stable forms of
pentose and hexose sugars
are five- or six-atom rings.
• These rings, known as
Haworth structures, are
produced from the reaction
of a carbonyl group and a
hydroxyl group in the
same molecule.
Learning Goal Draw and identify the Haworth structures of
monosaccharides.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Guide for Drawing Hayworth
Structures
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Cyclic Structure for Glucose
STEP 1 Turn the Fischer projection clockwise by 90°.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Cyclic Structure for Glucose
STEP 2 Fold clockwise to make a hexagon and bond the O
on carbon 5 to carbon 1.
• Place the carbon 6 group in the — CH2OH group
above carbon 5.
• Draw a bond between the oxygen of the — OH group
on carbon 5 to the carbonyl carbon.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Cyclic Structure for Glucose
STEP 3 Draw the new — OH group on carbon 1 below the
ring to give the α isomer or above the ring to give
the β isomer.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Mutarotation - and β-D-Glucose
When placed in solution,
• cyclic structures open and close
• -D-glucose converts to β-D-glucose and vice versa
• at any time, only a small amount of open chain forms
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Haworth Structures of Fructose
Fructose
• is a ketohexose
• forms a five-atom ring structure with carbon 2 at the right
corner of the ring
• forms when the — OH group on carbon 5 reacts with carbon
2 in the carbonyl group
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Write the cyclic forms of D-galactose.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
STEP 1 Turn the Fischer projection clockwise by 90°.
1
2
3
4
OH OH H
H
HOH2C
O
C
6
5
OH H
4
3
H
2
OH
1
H
5
6
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
STEP 2 Fold clockwise to make a hexagon and bond the O
on carbon 5 to the carbonyl group.
• Place the carbon 6 group above the ring.
• Write the — OH group on carbon 2
below the ring and the — OH groups
CH2OH
on carbon 3 and carbon 4 above
OH
OH
the ring.
O
H
C
OH H
H
H
H HO
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
STEP 3 Draw the new — OH group on carbon 1 below
the ring to give the α isomer or above the ring to give the
 isomer.


-D-Galactose
-D-Galactose
13.5 Chemical Properties of
Monosaccharides
Sugar alcohols such as D-sorbitol,
D-xylitol from D-xylose, and
D-mannitol from D-mannose are
used as sweeteners in many sugarfree products such as diet drinks
and sugarless gum as well as
products for people with diabetes.
Learning Goal Identify the products of oxidation or
reduction of monosaccharides; determine whether a
carbohydrate is a reducing sugar.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Oxidation of Monosaccharides
Monosaccharides in solution
• have small amounts of the open-chain form present
• have an aldehyde group with an adjacent hydroxyl group that
can be oxidized to carboxylic acid by an oxidizing agent
such as Benedict’s
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Oxidation of Monosaccharides
Sugar acids
• are produced from the oxidation of the aldehyde form as Cu2+
is reduced to Cu+
• are named by replacing the ose ending of the monosaccharide
with onic acid
A carbohydrate that reduces another substance (such as the open
chain form of D-glucose) is called a reducing sugar.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Oxidation: Fructose to Glucose
Fructose, a ketohexose,
• contains a ketone group, which usually can’t be oxidized
• can be oxidized in a basic Benedict’s solution when a
rearrangement occurs between the ketone group on carbon 2
and the hydroxyl group on carbon 1
• is then converted to glucose, which produces an aldehyde
group with an adjacent hydroxyl that can be oxidized
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Oxidation: Fructose to Glucose
Fructose, a ketohexose, rearranges to form glucose and is then
oxidized in Benedict’s.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Reduction of Monosaccharides
The reduction of the carbonyl group in monosaccharides
• produces sugar alcohols, which are also called alditols
• converts D-glucose to the sugar alcohol D-sorbitol
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Write the product of the reduction of D-mannose.
D-Mannose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Write the product of the reduction of D-mannose.
Reduction
D-Mannose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
D-Mannitol
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Chemistry Link to Health:
Glucose Testing
• Normally, blood glucose flows
through the kidneys and is
reabsorbed into the bloodstream.
• When the blood level exceeds
about 160 mg of glucose/dL of
blood, the kidneys cannot
reabsorb all of the glucose, and it
spills over into the urine, a
condition known as glucosuria.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Glucose Testing
• A symptom of diabetes mellitus is a high level of glucose in
the urine, which can be identified using Benedict’s test.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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13.6 Disaccharides
Lactose is a disaccharide found in milk and milk products. It
contains the monosaccharides galactose and glucose.
Learning Goal Describe the monosaccharide units and
linkages in disaccharides.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Disaccharides
A disaccharide
• consists of two monosaccharides linked together
• is formed when two monosaccharides combine in a
dehydration reaction
Monosaccharides
Disaccharide
glucose + glucose
glucose + galactose
glucose + fructose
maltose + H2O
lactose + H2O
sucrose + H2O
The most common disaccharides are maltose, lactose, and sucrose.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Maltose
Maltose is
• a disaccharide also known as malt sugar
• composed of two D-glucose molecules
• obtained from the hydrolysis of starch
• used in cereals, candies, and brewing
• found in both the  and β forms
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Formation of Maltose
Maltose is linked by an
-1,4-glycosidic bond
formed from the  — OH
on carbon 1 of the first
glucose and — OH on
carbon 4 of the second
glucose.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Lactose, Milk Sugar
Lactose
• is a
disaccharide
found in milk
and milk
products
• makes up 6–8%
of human milk
and about 4–
5% of cow’s
milk
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Lactose
Lactose is a disaccharide of β-D-galactose and α- or β-D-glucose.
The bond in lactose is a β-1,4-glycosidic bond because the —
OH group on carbon 1 of β-D-galactose forms a glycosidic bond
with the — OH group on carbon 4 of a D-glucose molecule.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Sucrose, Table Sugar
Sucrose, or table sugar,
• is obtained from sugar cane and
sugar beets
• consists of α-D-glucose and
β-D-fructose
• has an α,β-1,2-glycosidic bond
between carbon 1 of glucose and
carbon 2 of fructose
• cannot form an open chain and
cannot be oxidized
• cannot react with Benedict’s
reagent and is not a reducing
sugar
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Sucrose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Sweetness of Sweeteners
Sugars and artificial
sweeteners
• differ in sweetness
• are compared to
sucrose (table sugar),
which is assigned a
value of 100
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Artificial Sweeteners: Sucralose
Sucralose is
• marketed as Splenda
• made from sucrose by
replacing some of the
hydroxyl groups with
chlorine atoms
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Artificial Sweeteners: Aspartame
Aspartame is
• marketed as NutraSweet or Equal
• a noncarbohydrate sweetener made from aspartic acid
and a methyl ester of the amino acid phenylalanine
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Identify the monosaccharides in each of the following:
A. lactose
(1) α-D-glucose (2) β-D-fructose
(3) β-D-galactose
B. maltose
(1) α-D-glucose
(2) β-D-fructose
(3) β-D-galactose
C. sucrose
(1) α-D-glucose
(2) β-D-fructose
(3) β-D-galactose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Identify the monosaccharides in each of the following:
A. lactose
(1) α-D-glucose
(3) β-D-galactose
B. maltose
(1) α-D-glucose
C. sucrose
(1) α-D-glucose
(2) β-D-fructose
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Reducing Sugars
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health: Blood Types
Blood types A, B, AB,
and O are determined
by terminal saccharides
attached to the surface
of red blood cells.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health: Blood Types
Blood type
• O has three common terminal monosaccharides:
N-acetylglucosamine, galactose, and fucose
• A contains the same three monosaccharides, but in addition, a
molecule of N-acetylgalactosamine is attached to galactose in
the saccharide chain
• B also contains the same three monosaccharides, but in
addition, a second molecule of galactose is attached to the
saccharide chain
• AB consists of the same monosaccharides found in blood
types A and B
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health: Blood Types
The structures of
monosaccharides
N-acetylglucosamine,
galactose, and fucose
are as follows:
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health: Blood Types
Persons with
• type O blood, which contains the three common
monosaccharides, produce antibodies against blood types A,
B, and AB—they are universal donors
• blood types A, B, and AB can receive type O blood
• type AB blood, which contains all the terminal
monosaccharides, produce no antibodies to type A, B, or O
blood—they are universal recipients
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health: Blood Types
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Melibiose is a disaccharide that is 30 times sweeter than sucrose.
A. What are the monosaccharide units in melibiose?
B. What type of glycosidic bond links the monosaccharides?
C. Identify the structure as α- or β-melibiose.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Melibiose is a disaccharide that is 30 times sweeter than sucrose.
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Solution
Melibiose is a disaccharide that is 30 times sweeter than sucrose.
A. What are the monosaccharide units in melibiose?
-D-galactose and -D-glucose
B. What type of glycosidic bond links the monosaccharides?
-1,6-glycosidic bond
C. Identify the structure as α- or β-melibiose.
α-melibiose
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13.7 Polysaccharides
The polysaccharide
cellulose is composed of
glucose units connected by
β-1,4-glycosidic bonds.
Learning Goal Describe the structural features of
amylose, amylopectin, glycogen, and cellulose.
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Polysaccharides
Polysaccharides
• are formed when
monosaccharides are
joined together
• include amylose, amylopectin,
and cellulose, which are
polymers of α-D-glucose
α-D-Glucose
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Polysaccharides: Amylose, Amylopectin
The structure of amylose (a) is a straight-chain polysaccharide
of glucose units. The structure of amylopectin (b) is a branched
chain of glucose.
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Amylose
Amylose
• makes up about 20% of starch
• consists of 250 to 4000 α-D-glucose molecules connected
by α-1,4-glycosidic bonds in a continuous chain
• is called a straight-chain polymer even though the polymers
of amylose are actually coiled in helical fashion
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Amylopectin
Amylopectin
• makes up as much as 80% of starch
• is a branched-chain polysaccharide
• contains glucose molecules connected by α-1,4- and
α-1,6- glycosidic bonds
Starches hydrolyze easily in water and acid to give smaller
saccharides, called dextrins, which then hydrolyze to maltose
and finally glucose.
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Glycogen
Glycogen is
• a polymer of glucose that is stored in the liver and muscle
of animals
• hydrolyzed in our cells at a rate that maintains the blood level
of glucose and provides energy between meals
• similar to amylopectin, but it is more highly branched
The glucose units in glycogen are joined by α-1,4-glycosidic
bonds, with branches attached by α-1,6-glycosidic bonds that
occur every 10–15 glucose units.
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Cellulose
Cellulose, the major structural unit of wood,
• is a polysaccharide of glucose units in unbranched chains with
β-1,4-glycosidic bonds
• cannot form hydrogen bonds with water; thus, it is insoluble
in water
• gives a rigid structure to the cell walls in wood and fiber
• is more resistant to hydrolysis than are the starches
• cannot be digested by humans because humans cannot break
down β-1,4-glycosidic bonds
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Cellulose
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Study Check
Identify the polysaccharides and types of glycosidic
bonds in each of the following:
A.
B.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Identify the polysaccharides and types of glycosidic
bonds in each of the following:
A. cellulose
-1,4-glycosidic bonds
B. amylose
amylopectin
-1,4-glycosidic bonds
-1,4- and -1,6-glycosidic bonds
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Chapter 14 Carboxylic Acids,
Esters, Amines, and Amides
Surgical technicians prepare the
operating room and the patients for
surgery by
• creating a sterile environment in
the surgical room
• washing, shaving, and disinfecting
incision sites
During the surgery, a surgical
technician provides the sterile
instruments and supplies to the
surgeons and surgical assistants.
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14.1 Carboxylic Acids
A carboxylic acid contains a carboxyl group, which consists of a
hydroxyl group —OH attached to the carbon in a carbonyl group.
Learning Goal Give the IUPAC names and common names for
carboxylic acids; draw their condensed structural formulas or
skeletal formulas.
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IUPAC Names for Carboxylic Acids
In the IUPAC names of carboxylic acids,
• the -e in the alkane name is replaced with -oic acid
CH4
Methane
Methanoic acid
CH3—CH3
Ethane
Ethanoic acid
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Common Names of Carboxylic Acids
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Common Carboxylic Acids
A red ant sting contains formic
acid that irritates the skin.
The sour taste of vinegar is due
to ethanoic acid (acetic acid).
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Naming Carboxylic Acids
Give the IUPAC name for the
following carboxylic acid:
O
OH
SOLUTION:
ANALYZE Functional
THE
Group
PROBLEM carboxyl
Family
IUPAC Naming
carboxylic
acid
Replace the e in the alkane name
with oic acid and count from
carbon 1 of the carboxyl group
for any substituents.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Naming Carboxylic Acids
Give the IUPAC name for the
following carboxylic acid:
O
OH
STEP 1 Identify the carbon chain containing the carboxyl
group and replace the e in the alkane name with
oic acid.
pentanoic acid
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Naming Carboxylic Acids
Give the IUPAC name for the
following carboxylic acid:
STEP 2 Give the location and name of each substituent
on the main chain by counting the carboxyl
carbon as 1.
2-methylpentanoic acid
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Study Check
Give the IUPAC names of each compound.
A.
B.
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Solution
Give the IUPAC names of each compound.
A.
B.
2-methylpropanoic acid
3-bromobenzoic acid
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Give the skeletal structure for 4-chlorohexanoic acid.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Give the skeletal structure for 4-chlorohexanoic acid.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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14.2 Properties of Carboxylic Acids
Carboxylate salts are often used as
preservatives and flavor enhancers
in soups and seasonings.
Sodium propionate, a preservative,
is added to cheeses, bread, and
other bakery items to inhibit the
spoilage of the food by
microorganisms.
Learning Goal Describe the solubility and ionization of
carboxylic acids in water.
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Polarity of Carboxylic Acids
Carboxylic acids are strongly polar because they have
two polar groups:
• hydroxyl group (—OH)
• carbonyl group (C O)
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Solubility in Water
Carboxylic acids
• form hydrogen bonds with
many water molecules
• with one to four carbon atoms
are very soluble in water
As the number of carbons
increases, the solubility of
the carboxylic acid in water
is reduced.
Acetic acid forms
hydrogen bonds with
water molecules.
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Solubility in Water
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Acidity of Carboxylic Acids
Carboxylic acids
• are weak acids
• ionize in water to produce carboxylate ions
and hydronium ions
• can lose a proton because two oxygen atoms in the
carboxylate ion stabilize negative charge
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Write the balanced equation for the ionization of butanoic
acid in water and identify the carboxylate ion.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
Write the balanced equation for the ionization of butanoic acid
in water and identify the carboxylate ion.
O
CH3 —CH2—CH2—C—OH + H2O
O
CH3 —CH2—CH2—C—O–- + H3O+
carboxylate ion
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Neutralization of Carboxylic Acids
Carboxylic acid salts
• are a product of the neutralization of a carboxylic acid with a
strong base, such as NaOH or KOH
(carboxylic acid salt)
• are used as preservatives and flavor
enhancers
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Carboxylic Acid Salts
The carboxylate ion is named by replacing the ic acid ending of
the acid name with ate.
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Carboxylic Acid Salts
Carboxylic acid salts
• are ionic compounds with strong attractive forces between ions
• are solids at room temperature
• have high melting points
• are usually soluble in water
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Carboxylic Acid Salts
Carboxylic acid salts are used as preservatives and flavor
enhancers such as
• sodium propionate, which is used in cheese and breads
• sodium benzoate, which inhibits growth of mold and bacteria
and is added to fruit juices, margarine, relishes, salads, and jams
• monosodium glutamate, MSG, which is added to meats,
fish, vegetables, and baked goods to enhance flavor
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Write the equation for the reaction of propanoic acid with NaOH.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Write the equation for the reaction of propanoic acid with NaOH.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Carboxylic Acids in Metabolism
Carboxylic acids are part of the metabolic processes within our
cells. For example,
• during glycolysis, a molecule of glucose is broken down into
two molecules of pyruvate, the carboxylate salt of pyruvic acid
• during strenuous exercise, when oxygen levels are low
(anaerobic), pyruvic acid is reduced to give lactic acid or the
lactate ion
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Chemistry Link to Health:
Carboxylic Acids in Metabolism
In the critic acid cycle (Krebs
cycle), di- and tricarboxylic acids
are oxidized and decarboxylated
(loss of CO2) to produce energy
for cells.
At the start of the citric acid
cycle, citric acid is oxidized to a
five-carbon α-ketoglutaric acid:
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Chemistry Link to Health:
Carboxylic Acids in Metabolism
The citric acid cycle continues as α-ketoglutaric acid loses CO2
to give a four-carbon succinic acid. Then a series of reactions
converts succinic acid to oxaloacetic acid.
Some of the functional groups we have studied, including
hydration and oxidation, are part of the metabolic processes that
take place in our cells.
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14.3 Esters
By the 1800s, chemists discovered that
• salicin from the willow tree bark and
leaves was responsible for pain relief
• the body converts salicin to salicylic
acid, which irritates the stomach lining
Bayer soon discovered that an ester of
salicylic acid, acetylsalicylic acid, is less
irritating but still effective in pain relief.
Learning Goal Give the IUPAC and common names for an
ester; write the balanced chemical equation for the formation of
an ester.
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Esters
Esters are
• synthesized from the reaction of a carboxylic acid and alcohol
• found in fats and oils
• responsible for the aroma and flavor of bananas, oranges, and
strawberries
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Esterification
Esterification is
• the reaction of a carboxylic acid and alcohol in the presence
of an acid catalyst and heat to produce an ester
• the replacement of the hydrogen atom in the carboxylic acid
—OH group with an alkyl group from an alcohol
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Esterification
An example of esterification is the reaction of a ethanoic acid
with 1-propanol to produce an ester called propylethanoate,
responsible for the smell of pears.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Write the equation for the reaction of propanoic acid and
methanol in the presence of heat and an acid catalyst.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
Write the equation for the reaction of propanoic acid and
methanol in the presence of heat and an acid catalyst.
O
H+, Heat
CH3 —CH2—C—OH + CH3 —OH
O
CH3 —CH2—C—O—CH3 + H2O
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Naming Esters
The name of an ester consists of two words:
1. The first word indicates the alkyl part from the alcohol.
2. The second word is the carboxylate name of the
carboxylic acid.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Naming Esters
Esters have IUPAC and common names:
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Salicylic Acid from a Willow Tree
In 1899, the Bayer chemical company
• produced an ester of salicylic acid and acetic acid less
irritating to the stomach than salicylic acid
• called the ester acetylsalicylic acid (aspirin)
Many people take a daily low-dose aspirin, which has been
found to lower the risk of heart attack and stroke.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Chemistry Link to Health:
Salicylic Acid from a Willow Tree
Oil of wintergreen, or methyl salicylate, has a pungent, minty odor
and flavor and
• is used in skin ointments
• can pass through the skin
• acts as a counter-irritant, producing heat to soothe sore muscles
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Guide to Naming Esters
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Naming Esters
What is the IUPAC name of the following ester?
O
CH3 —CH2—C—O—CH2—CH3
SOLUTION:
ANALYZE Functional Group Family
THE
carboxyl
ester
PROBLEM
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
IUPAC
Write the alkyl name for
the carbon chain of the
alcohol, and change the
ic acid in the acid name
to ate.
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Naming Esters
What is the IUPAC name of the following ester?
O
CH3 —CH2—C—O—CH2—CH3
STEP 1 Write the name of the carbon chain from the
alcohol as an alkyl group.
O
CH3 —CH2—C—O—CH2—CH3 ethyl
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Guide to Naming Esters
What is the IUPAC name of the following ester?
STEP 2 Change the ic acid of the acid name to ate.
O
CH3 —CH2—C—O—CH2—CH3
ethyl propanoate
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Give the IUPAC and common names of the following
compound, which is responsible for the flavor and odor
of pears.
O
CH3 —C—O—CH2—CH2—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
Give the IUPAC and common names of the following
compound, which is responsible for the flavor and odor
of pears.
STEP 1 Write the name of the carbon chain from the
alcohol as an alkyl group.
O
CH3 —C—O—CH2—CH2—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
propyl
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Solution
Give the IUPAC and common names of the following
compound, which is responsible for the flavor and odor
of pears.
STEP 2 Change the ic acid of the acid name to ate.
O
CH3 —C—O—CH2—CH2—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
propyl ethanoate
propyl acetate
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Esters in Fruits
• Many of the fragrances of
perfumes and flowers and
the flavors of fruits are due
to esters.
• Small esters are volatile, so
we can smell them, and they
are soluble in water, so we
can taste them.
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Esters in Fruits and Flavoring
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Draw the structures of the following compounds:
A. 3-bromobutanoic acid
B. ethyl propanoate
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Draw the structures of the following compounds:
A. 3-bromobutanoic acid
O
Br
CH3 —CH—CH2—C—OH
B. ethyl propanoate
O
CH3 —CH2—C—O—CH2—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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14.4 Hydrolysis of Esters
Ethyl acetate is the solvent
in fingernail polish, plastics,
and lacquers.
O
CH3 —C—O—CH2—CH3
Learning Goal Draw the condensed structural formulas
for the products from acid and base hydrolysis of esters.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Acid Hydrolysis of Esters
In acid hydrolysis,
• an ester reacts with water to produce a carboxylic acid
and an alcohol
• a water molecule provides the —OH group to convert the
carbonyl group of the ester to a carboxyl group
• an acid catalyst and heat are required
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Base Hydrolysis (Saponification)
Base hydrolysis, or saponification,
• is the reaction of an ester with a strong base in the
presence of heat
• produces the salt of the carboxylic acid and an alcohol
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Write the organic products when methyl acetate reacts with
A. water, heat, and an acid catalyst
B. KOH, heat
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
Write the organic products when methyl acetate reacts with
A. water, heat, and an acid catalyst
O
+
H , Heat
CH3 —C—O—CH3 + H2O
O
CH3 —C—OH + CH3 —OH
B. KOH, heat
OO
CH
KOH
CH
3 —C—O—CH
3 3+ +KOH
3 —C—O—CH
Heat
Heat
OO
-–
++
-K
+ +CH
CH
—C—O
K
CH
—C—O
CH
3 3
3 —OH
3 —OH
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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14.5 Amines
Indigo used in blue dyes can be obtained from topical plants
such as Indigofera tinctoria.
Learning Goal Write the common names for amines; draw
the condensed structural formulas when given their names.
Classify amines as primary (1°), secondary (2°), or
tertiary (3°). Describe the solubility, ionization, and
neutralization of amines.
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Amines
Amines
• are derivatives of ammonia, NH3, in which one or more
hydrogen atoms are replaced with alkyl or aromatic groups
• contain N attached to one or more alkyl or aromatic groups
CH3 —CH2—CH2—N—CH3
CH3
H N H
H—N—CH2—CH3
CH3
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Classification of Amines
Amines are classified as primary, secondary, or tertiary:
• A primary (1°) amine has one carbon group bonded to the
nitrogen atom.
• A secondary (2°) amine has two carbon groups bonded to the
nitrogen atom.
• A tertiary (3°) amine has three carbon groups bonded to the
nitrogen atom.
H N H
H—N—CH3
CH3 —N—CH3
CH3
CH3
CH3
1°
2°
3°
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Classification of Amines
Amines have one or more carbon atoms bonded to the N atom.
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Naming Amines
Simple amines
• are named as alkylamines
• list the names of the alkyl groups bonded to the N atom
in alphabetical order in front of amine
• use prefixes to identify duplicate alkyl substituents
CH3 —CH2—NH2
Ethylamine
CH3 —NH—CH3
Dimethylamine
CH3 —N—CH2—CH3
Ethyldimethylamine
CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Give the common name for each amine and classify it as
primary, secondary, or tertiary.
A. CH3—CH2—CH2—NH2
CH3
B. CH3 —CH2—N—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Give the common name for each amine and classify it as
primary, secondary, or tertiary.
A. CH3—CH2—CH2—NH2
propylamine, 1°
CH3
B. CH3 —CH2—N—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
ethyldimethylamine, 3°
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Aromatic Amines
• The amine of benzene is named aniline.
• Alkyl groups on the N use the prefix N- with the alkyl name.
HN CH3
H—N—CH3
NH2
Cl
N-Methylaniline
Aniline
3-Chloroaniline
• Aniline is used to make many dyes, which give color to
wool, cotton, and silk fibers, as well as blue jeans.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Give the common name of each amine compound.
A.
CH3
CH3 —CH2—N—CH2—CH3
B.
H—N—CH2—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Give the common name of each amine compound.
A.
CH3
diethylmethylamine
CH3 —CH2—N—CH2—CH3
B.
H—N—CH2—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
N-ethylaniline
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Skeletal Structures of Amines
The skeletal structures show the shapes of amine molecules
with one or more alkyl groups bonded to the nitrogen atom.
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Solubility of Amines: Hydrogen Bonds
Primary and secondary amines with fewer than six carbons
are soluble in water; thus, they can form hydrogen bonds
with water molecules.
Tertiary amines can form hydrogen bonds only with water
molecules.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solubility of Amines: Hydrogen Bonds
Because amines contain a polar N —H bond, they form
hydrogen bonds with water.
•Primary (1°) amines, — NH2, can form more hydrogen
bonds than the secondary (2°) amines.
•Tertiary (3°) amines have no hydrogen on the nitrogen
atom and can form only hydrogen bonds with water from
the N atom.
Like alcohols, the smaller amines, including tertiary ones,
are soluble because they form hydrogen bonds with water.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solubility of Amines in Water
In amines with more than six carbon atoms,
• the effect of hydrogen bonding is diminished
• the nonpolar hydrocarbon chains of the amine decrease
its solubility in water
CH3
CH3 —CH2—N—CH2—CH2—CH2—CH2—CH2—CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Which of the following compounds are soluble in water?
A. CH3 — CH2 — CH2 — NH2
B. CH3 — CH2 — NH — CH3
C. CH3 — CH2 — CH2 — CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Which of the following compounds are soluble in water?
A. CH3 — CH2 — CH2 — NH2
B. CH3 — CH2 — NH — CH3
C. CH3 — CH2 — CH2 — CH3
Both A and B are amines that can form hydrogen bonds with
water and are therefore soluble in water. C is an alkane and
therefore not soluble in water.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Amines Act as Bases in Water
Ammonia (NH3), as well as 1° and 2° amines, acts as a
Brønsted–Lowry base because the lone electron pair on the
nitrogen accepts H+ from water to produce an ammonium ion
(NH4+) and a hydroxide ion (OH–).
NH3 + H2O
ammonia
CH3 — NH2 + H2O
methylamine
NH4+
+
OH–
ammonium ion hydroxide ion
CH3 — NH3+
+
OH–
methylammonium ion hydroxide ion
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Neutralization Forms Amine Salts
An amine salt forms when
• amines such as those responsible
for the odor in fish are neutralized
by an acid
• amines react as Brønsted–Lowry
bases in a neutralization reaction
with citric acid
The amines in fish react with
the
acid in lemon juice to
neutralize the “fishy” odor.
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Neutralization Forms Amine Salts
An ammonium salt is named by using its alkylammonium
ion name, followed by the name of the negative ion.
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Properties of Ammonium Salts
Amines are usually converted
to their ammonium salt before
being used as drugs. The
ammonium salts are solids at
room temperature, odorless and
soluble in water and body fluids.
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Properties of Ammonium Salts:
Medications
Ammonium salts are used as the active ingredients in
medications:
• Ephedrine is used as a bronchodilator in the decongestant
Sudafed.
• Diphenylhydramine, found in Benadryl, is used for relief of
itching and pain from skin irritations and rashes.
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Properties of Ammonium Salts:
Cocaine
The narcotic cocaine, extracted from coca leaves using an acidic
HCl solution, is smuggled and used illegally in the form of
cocaine hydrochloride, an ammonium salt.
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Properties of Ammonium Salts:
Cocaine
Cocaine hydrochloride, an ammonium salt, can be converted
back to its free amine or free base form, “crack cocaine” by
treating it with a strong base.
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Heterocyclic Amines
A heterocyclic amine consists of five or six atoms in the ring
with one or more nitrogen atoms.
N
N
H
H
Pyrrolidine
Pyrrole
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Chemistry Link to Health:
Alkaloids: Amines in Plants
Alkaloids are
• physiologically active compounds produced by plants that
contain heterocyclic amines
• used in anesthetics, in antidepressants, and as stimulants, and
many are habit forming
Nicotine is a stimulant that increases
• the level of adrenaline in the blood
• heart rate and blood pressure
Nicotine is addictive because it activates
pleasure centers in the brain.
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N
CH3
N
Nicotine
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Chemistry Link to Health:
Alkaloids: Amines in Plants
Caffeine
• is an alkaloid found in
coffee beans, tea,
chocolate, and soft drinks
• is a stimulant of the
central nervous system
• increases alertness but
may cause insomnia
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Chemistry Link to Health:
Alkaloids: Amines in Plants
Morphine and codeine are
• alkaloids, obtained from the
oriental poppy plant
• used as painkillers
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Study Check
Write the structural formula for
A. methylpropylamine
B. 2-chloroaniline
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Write the structural formula for
A. methylpropylamine
CH3 — CH2 — CH2 — NH — CH3
NH2
B. 2-chloroaniline
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
Cl
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15.1 Lipids
Lipids are
• biomolecules that contain fatty acids
or a steroid nucleus
• soluble in organic solvents but not
in water
• named for the Greek word lipos,
which means “fat”
• an important feature in cell
membranes, fat-soluble vitamins,
and steroid hormones
Steroid Nucleus
Learning Goal Describe the classes of lipids.
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Types of Lipids
Lipids are characterized by their structures.
1. Lipids such as waxes, fats, oils, and phospholipids are esters
that can be hydrolyzed to give fatty acids and other molecules.
2. Steroids, also lipids, do not contain fatty acids and cannot be
hydrolyzed. They are characterized by the steroid nucleus of
four fused carbon rings.
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General Structure of Lipids
Lipids are naturally occurring compounds that are soluble in
organic solvents but not in water.
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Study Check
Lipids are characterized by the presence of fatty acids or a
steroid nucleus. Which type is described by the following?
A. contains a fused four-membered ring system
B. contains long carbon chains
C. includes carbonyl groups
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Solution
Lipids are characterized by the presence of fatty acids or a
steroid nucleus. Which type is described by the following?
A. contains a fused four-membered ring system
steroid
B. contains long carbon chains
fatty acid
C. includes carbonyl groups
fatty acid
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Study Check
Which of the following is NOT a characteristic of lipids?
A. may contain a carboxylic acid group
B. may contain a four-ring structure
C. soluble in water
D. mostly nonpolar
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Solution
Which of the following is NOT a characteristic of lipids?
A. may contain a carboxylic acid group
B. may contain a four-ring structure
C. soluble in water
D. mostly nonpolar
The answer is C.
Lipids are nonpolar and therefore are NOT soluble in water.
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15.2 Fatty Acids
We might think of saturated
fatty acids as chips with
regular shapes that stack
closely together in a can.
Similarly, irregularly shaped
chips would be like
unsaturated fatty acids that do
not fit closely together.
Learning Goal Draw the condensed structural formula for a
fatty acid and identify it as saturated or unsaturated.
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Fatty Acids
Fatty acids are
• long, unbranched carbon chains with a carboxylic acid
group at the end
• typically 12– to 18–carbon atoms long
• insoluble in water because of the long carbon chain
• saturated when they do not contain C C double bonds
in the carbon chain
• unsaturated when they contain C C double bonds in
the carbon chain
Core Chemistry Skill Identifying Fatty Acids
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Drawing Fatty Acids
• In a skeletal formula of a fatty acid, the ends and bends of
the line are the carbon atoms.
• The structural formula of lauric acid can be drawn in
several forms.
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Saturated Fatty Acids
Fatty acids can be saturated, with only C — C single bonds
in the carbon chain.
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Monounsaturated Fatty Acids
Fatty acids can be monounsaturated, with only one double
C C bond in the carbon chain.
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Polyunsaturated Fatty Acids
Fatty acids can be polyunsaturated, with at least two double
C C bonds in the carbon chain.
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Cis and Trans Unsaturated Fatty
Acids
• Unsaturated fatty acids can be drawn as cis and trans isomers.
• Oleic acid is a monounsaturated fatty acid found in olives, with
one double bond at carbon 9.
Almost all naturally occurring unsaturated fatty acids have one or more
cis double bonds.
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Essential Fatty Acids
Humans
• are capable of synthesizing some fatty acids from
carbohydrates or other fatty acids
• cannot synthesize sufficient amounts of polyunsaturated fatty
acids such as linoleic acid, linolenic acid, and arachidonic acid
Because these polyunsaturated fatty acids must be obtained from
the diet, they are known as essential fatty acids.
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Properties of Saturated Fatty Acids
Saturated fatty acids
• contain only single C — C bonds and fit close together in a
regular pattern
• have strong dispersion forces between long carbon chains
• have higher melting points and are usually solids at
room temperature
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Properties of Saturated Fatty Acids
In unsaturated fatty acids,
the cis double bonds cause
the carbon chain to bend or
kink, giving the molecules
an irregular shape and
allowing fewer interactions
between molecules.
The reduced interactions in fatty acids with cis bonds reduces the
melting point of the molecules.
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Study Check
Consider the condensed structural formula for oleic acid.
A. Why is this molecule an acid?
B. How many total carbon atoms are in oleic acid?
C. Is this a saturated, monounsaturated, or polyunsaturated
fatty acid?
D. Is it likely to be a solid or liquid at room temperature?
E. Would it be soluble in water?
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Consider the condensed structural formula for oleic acid.
A. Why is this molecule an acid?
It contains a carboxylic acid functional group.
B. How many total carbon atoms are in oleic acid?
Oleic acid contains 18 carbon atoms.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Consider the condensed structural formula for oleic acid.
C. Is this a saturated, monounsaturated, or polyunsaturated
fatty acid?
Oleic acid is a monounsaturated fatty acid.
D. Is it likely to be a solid or liquid at room temperature?
It is a liquid at room temperature.
E. Would it be soluble in water?
The long carbon chain makes it insoluble in water.
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Prostaglandins
Prostaglandins
• are hormone-like substances produced in cells
• are also known as eicosanoids, formed from arachidonic acid,
a polyunsaturated fatty acid with 20 carbon atoms
• differ by the substituents attached to the five-carbon ring
• have many functions, such as lowering or raising blood
pressure and stimulating contraction and relaxation of
the smooth muscle of the uterus
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Prostaglandins: NSAIDs
Nonsteroidal anti-inflammatory drugs (NSAIDs) block
production of prostaglandins, decreasing pain and inflammation.
NSAIDs include naproxen (Aleve and Naprosyn), ketoprofen
(Actron), and nabumetone (Relafen).
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Chemistry Link to Health:
Omega-6 Fatty Acids
• Unsaturated fats such as those in vegetable oils and fish are
recognized as more beneficial to health than saturated fats.
• Vegetables contain omega-6 acids, meaning the first double
bond occurs at carbon 6 counting from the methyl end of the
carbon chain. Examples of omega-6 acids are linoleic and
arachidonic acids.
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Chemistry Link to Health:
Omega-3 Fatty Acids
Fish has high levels of omega-3 acids, meaning the first double
bond occurs at carbon 3, counting from the methyl end of the
chain. Examples of omega-3 acids include linolenic,
eicosapentaenoic, and docosahexaenoic acids.
Cold-water fish are a source of omega-3 fatty acids.
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Chemistry Link to Health:
Omega-3 Fatty Acids
In atherosclerosis and heart disease,
• cholesterol forms plaques that adhere to the walls of the
blood vessels
• blood pressure rises as blood has to squeeze through a smaller
opening in the blood vessel
• more plaque forms; there is also a possibility of blood clots
blocking the blood vessels and causing a heart attack
Omega-3 fatty acids lower the tendency of blood platelets to
stick together, reducing the possibility of blood clots.
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Study Check
Label each of the following fatty acids as saturated,
monounsaturated, or polyunsaturated.
A. linolenic acid
B. palmitoleic acid
C. stearic acid
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Solution
Label each of the following fatty acids as saturated,
monounsaturated, or polyunsaturated.
A. linolenic acid
polyunsaturated
B. palmitoleic acid
monounsaturated
C. stearic acid
saturated
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15.3 Waxes and Triacylglycerols
Natural waxes are found on the
surface of fruits and on the leaves
and stems of plants, where they help
prevent loss of water and damage
from pests.
Waxes on the skin, fur, and feathers
of animals provide a waterproof
coating.
Learning Goal Draw the condensed structural formula for a
wax or triacylglycerol produced by the reaction of a fatty acid
and an alcohol or glycerol.
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Waxes
Waxes are
• esters of saturated fatty acids and long-chain alcohols, each
containing from 14 to 30 carbon atoms
• coatings that prevent loss of water by leaves of plants
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Typical Waxes
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Triacylglycerols
In the body, fatty acids are stored as triacylglycerols
(triglycerides), which are
• esters of glycerol (a trihydroxy alcohol) and fatty acids
• formed when three hydroxyl groups of glycerol react with the
carboxyl groups of three fatty acids
• named by changing glycerol to glyceryl and naming the fatty
acids as carboxylates
Core Chemistry Skill Drawing Structures for Triacylglycerols
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Triacylglycerol: Glyceryl Tristearate
The name of the fatty acid formed with three stearic acids
becomes glyceryl tristearate.
The common name of this compound is tristearin.
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Mixed Triacylglycerols
Triacylglycerol may contain different fatty acids, such as the
triacylglycerol made from stearic, oleic, and palmetic acids.
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Triacylglycerols: Energy Storage
Triacylglycerols are the major form of energy storage for
animals.
• Animals that hibernate eat large quantities of plants, seeds,
and nuts that are high in calories.
• As the external temperature drops, the animal goes into
hibernation and the body temperature drops to nearly
freezing, reducing cellular activity, respiration, and heart rate.
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Triacylglycerols: Energy Storage
• During hibernation, the
animal’s stored fat in the
form of triacylglycerols is
its only source of energy.
Prior to hibernation, a polar bear
eats food with a high caloric content.
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Study Check
What are the fatty acids in the following triacylglycerol?
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
What are the fatty acids in the following triacylglycerol?
stearic acid
oleic acid
myristic acid
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Drawing the Structure of a
Triacylglycerol
Draw the condensed structural formula for glyceryl
tripalmitoleate (tripalmitolein).
SOLUTION:
Glyceryl tripalmitoleate (tripalmitolein) is the triacylglycerol that
contains ester bonds between glycerol and three palmitoleic
acids acid molecules.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Drawing the Structure of a
Triacylglycerol
Draw the condensed structural formula for glyceryl
tripalmitoleate (tripalmitolein).
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Draw the condensed structural formula for the triacylglycerol
containing three molecules of myristic acid (14:0).
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Draw the condensed structural formula for the triacylglycerol
containing three molecules of myristic acid (14:0).
O
CH2—O—C—(CH2)12 —CH3
O
CH—O—C—(CH 2)12 —CH3
O
CH2—O—C—(CH2)12 —CH3
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Melting Points of Fats and Oils
A fat
• is usually solid at room temperature
• usually comes from animal sources such as meat, whole milk,
butter, and cheese
An oil
• is usually liquid at room temperature
• is usually obtained from a plant source such as palm oil and
coconut oil
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Oils with Unsaturated Fatty Acids
Oils from
• olive and peanut are monounsaturated; they contain large
amounts of oleic acid
• corn, cottonseed, safflower seed, and sunflower seed are
polyunsaturated because they contain large amounts of
fatty acids with two or more double bonds
• palm and coconut are solids at room temperature because
they consist mostly of saturated fatty acids
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Saturated and Unsaturated
Melting Points
Saturated fatty acids
• have higher melting
points than unsaturated
fatty acids because they
pack together more
tightly
• are usually found in
animal fats and in
coconut and palm oils
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Percent Saturated and Unsaturated
Fatty Acids in Fats and Oils
Vegetable oils have low melting points because they have a
higher percentage of unsaturated fatty acids than do animal fats.
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15.4 Chemical Properties of
Triacylglycerols
Many soft margarines, stick margarines, and solid shortenings
are produced by the partial hydrogenation of vegetable oils.
Learning Goal Draw the condensed structural formula for
the product of a triacylglycerol that undergoes
hydrogenation, hydrolysis, or saponification.
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Triacylglycerols: Hydrogenation
In hydrogenation reactions,
• double bonds in unsaturated fatty acids react with hydrogen
gas to produce carbon–carbon single bonds
• hydrogen gas is bubbled through the heated oil, typically in
the presence of a nickel catalyst
Core Chemistry Skill Identifying the Products for the
Hydrogenation, Hydrolysis, and Saponification of a
Triacylglycerol
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Hydrogenation Reactions
When hydrogen adds to all of the double bonds of glyceryl
trioleate (triolein) using a nickel catalyst, the product is the
saturated fat glyceryl tristearate (tristearin).
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Hydrogenation Reactions
In commercial hydrogenation,
• the addition of hydrogen is
stopped before all the double
bonds in a liquid vegetable oil
become completely saturated
• the partial hydrogenation of a
liquid vegetable oil changes it
to a soft, semisolid fat
• the more saturated product has
a higher melting point
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Study Check
What products are obtained from the complete hydrogenation
of glyceryl trioleate?
A. glycerol and three oleic acids
B. glyceryltristearate
C. glycerol and three stearic acids
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Solution
What products are obtained from the complete hydrogenation
of glyceryl trioleate?
B. glyceryltristearate
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Chemistry Link to Health:
Trans Fatty Acids
Unsaturated fatty acids can be
• cis, with bulky groups on the same side of C
• trans, with bulky groups on opposite sides of C
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
C
C
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Hydrogenation: Trans Fatty Acids
During hydrogenation,
• double bonds are converted to C — C single bonds
• a small number of the cis double bonds are converted to more
stable trans double bonds, causing a change in the overall
structure of the fatty acids
In the body, trans fatty acids
• behave like saturated fatty acids
• are estimated to be 2–4% of our total calories
• raise LDL-cholesterol and lower HDL-cholesterol
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Hydrogenation: Trans Fatty Acids
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Trans Fatty Acids in Foods
Foods containing naturally occurring trans fatty acids include
milk, eggs, and beef.
Foods that contain trans fatty acids from the hydrogenation
process include
• deep-fried foods
• bread, baked goods, and cookies
• crackers and chips
• stick and soft margarines
• vegetable shortening
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Study Check
Which of the following statements are true and which are false?
A. There are more unsaturated fats in vegetable oils.
B. Vegetable oils have higher melting points than fats.
C. Hydrogenation of oils converts some cis double bonds to
trans double bonds.
D. Animal fats have more saturated fats.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Solution
Which of the following statements are true and which are false?
A. True There are more unsaturated fats in vegetable oils.
B. False Vegetable oils have higher melting points than fats.
C. True Hydrogenation of oils converts some cis double bonds
to trans double bonds.
D. True Animal fats have more saturated fats.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Study Check
Draw the condensed structural formula for the product of a
glyceryl tripalmitoleate that undergoes hydrogenation.
O
CH2—O—C—(CH 2)7 —CH
O
CH—(CH 2)5 —CH3
CH2—O—C—(CH2)7 —CH
O
CH—(CH2)5 —CH3 + 3H2
CH2—O—C—(CH 2)7 —CH
CH—(CH 2)5 —CH3
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
Ni
© 2015 Pearson Education, Inc.
Solution
Draw the condensed structural formula for the product of a
glyceryl tripalmitoleate that undergoes hydrogenation.
O
CH2—O—C—(CH 2)14 —CH3
O
+ 3H2
glyceryl
tripalmitoleate
Ni
CH2—O—C—(CH 2)14 —CH3
O
CH2—O—C—(CH 2)14 —CH3
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Hydrolysis
In hydrolysis,
• triacylglycerols split into glycerol and three fatty acids
• a strong acid, HCl or H2SO4, or digestive enzymes called
lipases are required
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Saponification and Soap
Saponification
• is the reaction of a fat with a strong base such as NaOH in
the presence of heat
• splits triacylglycerols into glycerol and the sodium salts of
fatty acids
• is the process of forming “soaps” (salts of fatty acids)
• with NaOH gives solid soaps that can be molded into
different shapes
• with KOH gives softer, liquid soaps
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Saponification and Soap
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Organic and Lipid Reactions
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Study Check
Write the equation for the reaction catalyzed by the enzyme
lipase that hydrolyzes glyceryl trilaurate (trilaurin) during the
digestion process.
O
CH2—O—C—(CH2)10 —CH3
O
Lipase
CH2—O—C—(CH2)10 —CH3 + 3H2O
O
CH2—O—C—(CH2)10 —CH3
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Solution
Write the equation for the reaction catalyzed by the enzyme
lipase that hydrolyzes glyceryl trilaurate (trilaurin) during the
digestion process.
O
CH2—OH
glyceryl
trilaurate
Lipase
+ 3H2O
CH2—OH
HO—C—(CH2)10 —CH3
O
+
HO—C—(CH2)10 —CH3
O
CH2—OH
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
HO—C—(CH2)10 —CH3
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15.5 Phospholipids
The phospholipids are a
family of lipids similar in
structure to
triacylglycerols; they
include
glycerophospholipids
and sphingomyelin.
Fatty acid
G
l
y
c
e
r
o
l
Glycerophospholipids are
major constituents of
membranes and are
responsible for the
membrane being a
bilayer.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
Fatty acid
PO4
Amino
alcohol
Glycerophospholipid
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Glycerophospholipids
Glycerophospholipids contain
• two fatty acids that form
ester bonds with the first and
second hydroxyl groups of
glycerol
• a hydroxyl group that forms
an ester with phosphoric
acid, which forms another
phosphoester bond with an
amino alcohol
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
Fatty acid
G
l
y
c
e
r
o
l
Fatty acid
PO4
Amino
alcohol
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Sphingomyelin
Sphingomyelin
• contains sphingosine
instead of glycerol
• contains a fatty acid,
phosphate, and an
amino alcohol
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
S
p
h
i
n
g
o
s
i
n
e
Fatty acid
PO4
Amino
alcohol
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Amino Alcohols
Amino alcohols found in glycerophospolipids
• are choline, erine, and ethanolamine
• are ionized at physiological pH of 7.4
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Lecithin and Cephalin
Lecithin and cephalin are types of glycerophospholipids that are
• abundant in brain and nerve tissues
• found in egg yolk, wheat germ, and yeast
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Structure and Polarity of a
Glycerophospholipid
Glycerophospholipids
• have both polar and nonpolar regions that allow them to
interact with polar and nonpolar substances
• have a polar head containing the ionized amino alcohol
and phosphate portion, which is strongly attracted to
water
• have a nonpolar hydrocarbon tail portion soluble only in
nonpolar substances such as lipids
• are the most abundant lipids in cell membranes and play
an important role in cellular permeability
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
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Structure and Polarity of a
Glycerophospholipid
(a) The components of a typical
glycerophospholipid: an amino alcohol,
phosphoric acid, glycerol, and two fatty
acids. (b) In a glycerophospholipid, a polar
“head” contains the ionized amino alcohol
and phosphate, while the hydrocarbon
chains of two fatty acids make up the
nonpolar “tails.” (c) A simplified drawing
indicates the polar region and the nonpolar
region.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Study Check
Identify each of the following as a fatty acid, a triacylglycerol, an
amino alcohol, or a glycerophospholipid.
A. glyceryl trioleate
B. cephalin
C. choline
D. palmitic acid
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
Identify each of the following as a fatty acid, a triacylglycerol, an
amino alcohol, or a glycerophospholipid.
A. glyceryl trioleate
B. cephalin
triacylglycerol
glycerophospholipid
C. choline
D. palmitic acid
amino alcohol
fatty acid
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Study Check
Draw the condensed structural formula of a cephalin that contains
stearic acid and serine.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
Draw the condensed structural formula of a cephalin that contains
stearic acid and serine.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Sphingomyelin
In a sphingomyelin,
• the amine group of sphingosine forms an amide bond to a
fatty acid
• the hydroxyl group forms an ester bond with phosphate, which
forms another phosphoester bond to choline or ethanolamine
Sphingomyelins are abundant in the white matter of the myelin
sheath, a coating surrounding the nerve cells that increases the
speed of nerve impulses and insulates and protects the nerve cells.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Sphingomyelin
Structure of a sphingomyelin containing myristic acid and
choline.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Study Check
Palmitic acid, the 16-carbon saturated fatty acid, is the most
common fatty acid found along with the ionized amino alcohol
choline in the sphingomyelin of eggs.
Draw the condensed structural formula for this sphingomyelin.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
Palmitic acid, the 16-carbon saturated fatty acid, is the most
common fatty acid found along with the ionized amino alcohol
choline in the sphingomyelin of eggs.
Draw the condensed structural formula for this sphingomyelin.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
15.6 Steroids: Cholesterol, Bile Salts,
and Steroid Hormones
High- and low-density lipoproteins transport cholesterol
between the tissues and the liver.
Learning Goal Describe the structures of steroids.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Steroid Nucleus
A steroid nucleus consists of
• three cyclohexane rings and one
cylopentane ring, fused together
• rings designated as A, B, C,
and D
• numbered carbon atoms
beginning in ring A
• two methyl groups at positions
18 and 19
Steroid nucleus
Core Chemistry Skill Identifying the Steroid Nucleus
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Cholesterol
Cholesterol
• is the most important and
abundant steroid in the body
• has an hydroxyl group (— OH)
on (carbon 3)
• has a double bond between
carbons 5 and 6
• has methyl groups at carbons 10
and 13
• has an alkyl chain at carbon 17
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
Cholesterol
© 2015 Pearson Education, Inc.
Cholesterol in the Body
Cholesterol
• is obtained from meats, milk,
and eggs
• is synthesized in the liver
• is needed for cell membranes,
brain and nerve tissue, steroid
hormones, and vitamin D
• clogs arteries when high levels
form plaque
Cross-sections of arteries show
how plaque clogs the arteries.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
A normal, open artery.
An artery clogged by
cholesterol plaque
© 2015 Pearson Education, Inc.
Cholesterol in Foods
Cholesterol
• is considered elevated if plasma cholesterol exceeds 200 mg/dL
• is synthesized in the liver and obtained from foods
A diet that is low in foods containing cholesterol and saturated fats
appears to be helpful in reducing the serum cholesterol level.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Cholesterol in Foods
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Study Check
Match the components of the cholesterol molecule with
the following:
___ carbon chain
___ hydroxyl group
___ steroid nucleus
___ methyl group
D
B
A
C
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Solution
Match the components of the cholesterol molecule with
the following:
D carbon chain
A hydroxyl group
C steroid nucleus
B methyl group
D
B
A
C
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Bile Salts
Bile salts
• are synthesized in the liver from
cholesterol and stored in the
gallbladder
• have polar and nonpolar regions
that act like soaps to make fat
soluble in water
• help in absorption of cholesterol
When large amounts of cholesterol
accumulate in the gallbladder,
gallstones are formed.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
Gallstones form in the gallbladder
when cholesterol levels are high.
© 2015 Pearson Education, Inc.
Bile Salts
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Lipoproteins: Lipid Transport
Lipids are nonpolar and made more soluble by combining them
with glycerophospholipids and proteins to form water-soluble
complexes called lipoproteins.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Lipoproteins
Lipoproteins
• surround nonpolar
lipids with polar
lipids and protein
for transport
to cells
• are soluble in
water because the
surface consists of
polar lipids
A spherical lipoprotein particle
surrounds nonpolar lipids with polar
lipids and protein for transport to
body cells.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Types of Lipoproteins
Lipoproteins
• differ in density, composition, and function
• include low-density lipoproteins (LDLs) and high-density
lipoproteins (HDLs)
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Transport of Lipoproteins in the Body
Lipoproteins such as HDLs and LDLs transport nonpolar lipids and cholesterol
to cells and the liver.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Chylomicrons
•Chylomicrons are the largest and most dense lipoprotein.
Chylomicrons enter the lymphatic system and travel throughout
the body, breaking down and getting smaller as triglycerides are
detached from the chylomicron and distributed to cells and
adipose sites. Most matter in chylomicrons is used during this
process, and the remaining matter in the chylomicron returns to
the liver and is recycled as more triglyceride or is inserted into
another lipoprotein.
Very Low-Density Lipoproteins
•Very low-density lipoproteins (VLDL) travel throughout the body.
VLDLs have a smaller concentration of fat to protein at the beginning,
with more protein than fat. However, as they travel throughout the
body and give off matter, the concentration of cholesterol to protein
increases, and they essentially become low-density lipoproteins
(LDL) once they increase their concentration of fat to protein enough.
Low-Density Lipoprotein
•Low-density lipoproteins, or LDLs, transport cholesterol to
replenish cell cholesterol supply. LDLs are then lysed in the liver
and secreted into the gallbladder and the intestinal system for
waste. Excess LDLs in the bloodstream may break down and
release cholesterol into bloodstream, causing plaquing of the
arteries. A high ratio of LDLs to HDLs is more than 4 to 1, while a
normal ratio is around 3 to 1.
High-Density Lipoproteins
•High-density lipoproteins (HDLs) transport excess cholesterol
out of the bloodstream and bring it into liver, where it is
destroyed or recycled. HDLs are seen as “healthy” lipoproteins
because of their “job” of clearing cholesterol out of the
bloodstream.
Steroid Hormones
Steroid hormones are
• chemical messengers that serve as a communication system
for the body
• produced from cholesterol
• male sex hormones, testosterone and androsterone
• female sex hormones, estrogens and progesterone
• adrenal corticosteroids from adrenal glands
– mineralocorticoids (electrolyte balance)
– glucocorticoids (regulate glucose level)
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Structures of Steroid Hormones
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Chemistry Link to Health:
Anabolic Steroids
Anabolic steroids
• are derivatives of testosterone
• are used illegally to increase muscle mass
• have side effects including fluid retention, hair growth, sleep
disturbance, and liver damage
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Adrenal Corticosteroids
Steroid hormones called adrenal corticosteroids
• are produced by the adrenal glands located on the top
of each kidney
• include aldosterone, which regulates electrolytes and
water balance by the kidneys
• include cortisone, a glucocorticoid, which increases
blood glucose level and stimulates the synthesis of
glycogen in the liver
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition
© 2015 Pearson Education, Inc.
Adrenal Corticosteroids…