Transcript Quiz 2

INTRODUCTION TO ORGANIC
COMPOUNDS
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3.1 Life’s molecular diversity is based on the
properties of carbon
 Carbon’s ability to form diverse bonds makes it
important for the diversity of life
– Carbon-based molecules are called organic
compounds
– By sharing electrons, carbon can bond with up to
four other atoms
– By doing so, it can branch in up to four directions
– Can form highly branched or unbranched structures
– Can make single or double bonds, ex.
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Each carbon thus acts as a central intersection point from which
any carbon based molecule can branch off in up to four directions.
•
Using carbon as our building block we can make molecules as
complicated as the US highway system.
3.1 Life’s molecular diversity is based on the
properties of carbon
 Methane (CH4) is one of the simplest organic
compounds
– Four covalent bonds link four hydrogen atoms to the
carbon atom
– Each of the four lines in the formula for methane
represents a pair of shared electrons
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Structural
formula
Ball-and-stick
model
Space-filling
model
Methane
The four single bonds of carbon point to the corners
of a tetrahedron.
The Formation of Bonds with Carbon
• With four valence electrons, carbon can form
four covalent bonds with a variety of atoms
• This tetravalence makes simple and small, or
large and complex molecules possible
Double bond
Simple
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Complex
Molecular Diversity Arising from Carbon Skeleton
Variation
• Carbon chains form the skeletons of most
organic molecules
• Carbon chains vary in length and shape
• Carbon chains may be long, short, branched,
vary in location of double bonds, may even
contain ring structures
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Fig. 4-5
Carbon Chains
Ethane
Propane
1-Butene
(a) Length
Butane
2-Butene
(c) Double bonds
2-Methylpropane
(commonly called isobutane)
(b) Branching
Extra challenge for the fun of it:
C6H14
Now draw this a different way.
Cyclohexane
(d) Rings
Benzene
These molecules are all examples of hydrocarbons: molecules that contain H and C
− Are nonpolar molecules and nonpolar bonds
−Their bonds contain a great deal of energy
−Our body utilizes this and stores energy in the form of fats
Fats contain a large hydrocarbon component
Ethane
Propane
1-Butene
(a) Length
Butane
(b) Branching
2-Butene
(c) Double bonds
2-Methylpropane
(commonly called isobutane)
Cyclohexane
(d) Rings
Benzene
Checkpoint
• Carbon bonding properties are:
– Can form single or double bonds
– ?
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Checkpoint
• Carbon bonding properties are:
– Can form single or double bonds
– Can form diverse structures
– Can form 4 covalent bonds
– Can form extensive branched or unbranched C
skeletons
– Many other properties
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
3.1 Life’s molecular diversity is based on the
properties of carbon
 Methane and other compounds composed of only
carbon and hydrogen are called hydrocarbons
– Carbon, with attached hydrogens, can bond together in
chains of various lengths
– Web activity
– Gumdrops
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Propane
Ethane
Length.
Carbon skeletons vary in length.
Isomers – molecules
with the same
molecular formula but
different structure
Isobutane
Butane
Branching. Skeletons may be unbranched or branched.
Which two molecules
are isomers?
2-Butene
1-Butene
Double bonds.
Skeletons may have double bonds,
which can vary in location.
Cyclohexane
Rings.
Benzene
Skeletons may be arranged in rings.
Some more examples of isomers
Pentan
e
cis isomer: The two Xs are
on the same side.
L isomer
2-methyl
butane
trans isomer: The two Xs are
on opposite sides.
D isomer
3.2 Characteristic chemical groups help determine
the properties of organic compounds
 An organic compound has unique properties that
depend upon
– The size and shape of the molecule and
– The groups of atoms (functional groups) attached to it
 Addition of a functional group affects a
biological molecule’s function in a characteristic
way
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Estradiol
Female lion
Testosterone
Male lion
3.3 Cells make a huge number of large molecules
from a small set of small molecules
 There are four classes of biological molecules
 All are a type of polymer
– Carbohydrates
– Proteins
– Lipids
– Nucleic acids
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3.3 Cells make a huge number of large molecules
from a small set of small molecules
 The four classes of biological molecules contain
very large molecules
– They are often called macromolecules because of
their large size
– They are also called polymers because they are made
from identical building blocks strung together
– The building blocks are called monomers
– Leggos
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3.3 Cells make a huge number of large molecules
from a small set of small molecules
Polymer
Monomer
Carbohydrate
Sugars or saccharides
Protein
Amino Acids
Lipid
Fatty acids, glycerol
Nucleic Acids
Nucleotides
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3.3 Cells make a huge number of large molecules
from a small set of small molecules
 Monomers are linked together to form polymers
through dehydration reactions, which remove
water
 Polymers are broken apart by hydrolysis, the
addition of water
 All biological reactions of this sort are mediated by
enzymes, which speed up chemical reactions in
cells
 Enzymes are always proteins
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CARBOHYDRATES
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Carbohydrates
 Carbohydrates include sugars and the polymers of sugars
 The simplest carbohydrates are monosaccharides, or single
sugars
 For example: glucose, fructose,
 Disaccharides are compose of two single sugars
 For example: sucrose (composed of a fructose and a glucose)
Lactose (glucose and galactose)
 Carbohydrate macromolecules are polysaccharides,
polymers composed of many sugar building blocks
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The Synthesis and Breakdown of Polymers
 A condensation reaction or more specifically a dehydration
reaction/synthesis occurs when two monomers bond
together through the loss of a water molecule
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The Synthesis and Breakdown of Polymers
 Polymers are disassembled to monomers by hydrolysis, a
reaction that is essentially the reverse of the dehydration
reaction
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Starch granules in
potato tuber cells
Glycogen
granules
in muscle
tissue
Cellulose fibrils in
a plant cell wall
Cellulose
molecules
STARCH
Glucose
monomer
GLYCOGEN
CELLULOSE
Hydrogen bonds
Can man live on soda pop?
How Bad Are Sugary Soft Drinks?
• There is a correlation between increased daily
consumption of sweetened beverages and
obesity.
− Nutritionists finger high fructose corn syrup
consumption as a major culprit in the nation's
obesity crisis. The inexpensive sweetener flooded
the American food supply in the early 1980s, just
about the time the nation's obesity rate started its
unprecedented climb. SF Chronicle 2004
• Beverage manufacturers argue that correlation and cause
are not the same.
• Studies funded by the beverage industry conclude that
soft drinks have no special role in obesity.
• A single 12-ounce can of soda has as much as 13 teaspoons of
sugar in the form of high fructose corn syrup
• People often consume up to 50 tsp of sugar a day
How Bad Are Sugary Soft Drinks?
•
A cautionary note comes from an analysis of industry-funded
versus independently-funded nutritional studies.
•
Industry-funded studies are more likely to produce conclusions
favorable to the industry than independently-funded work.
• A direct link between sugary drinks and obesity in
the U.S. population cannot be proven.
• So. . . “is it simply -- that we're eating too many
empty calories in ever-increasing portion sizes? Or
does the fructose in all that corn syrup do something
more insidious -- literally short-wire our metabolism
and force us to gain weight?” SF Chronicle 2004
How Bad Are Sugary Soft Drinks?
•
What is high fructose corn syrup?
− Made from glucose that is already in corn starch
− Enzymes breakdown the starch to glucose and then convert some of
this glucose to fructose , so there is more fructose than normally
would be there
− Fructose is 30% more sweet than glucose or sucrose so people love
it!
− The industry loves HFCS because is dissolves easily and is cheap to
make
 Fructose digestion and absorption differ from glucose
− Fructose does not make as many chemicals (leptin) that curb the
appetite and glucose does
− Fructose is more readily converted to fat by bodily enzymes
•
Whatever you believe, if you want to lose weight you are well-advised to
consume fewer sweetened drinks.
PROTEINS
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1.
What are the constituent parts of proteins?
2.
What is the primary fuel source for muscles?
3.
Explain why it is so difficult to study how
specific nutritional changes impact an athlete's
performance.
4.
Will reading this article change how you think
about Power Bars, carbohydrate loading, etc?
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3.11 Proteins are essential to the structures and
functions of life
 A protein is a polymer built from various
combinations of 20 amino acid monomers
– Proteins have unique structures that are directly related
to their functions
– Enzymes, proteins that serve as metabolic catalysts,
regulate the chemical reactions within cells
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3.12 Proteins are made from amino acids linked
by peptide bonds
 Amino acids, the building blocks of proteins,
have an amino group and a carboxyl group
– Both of these are covalently bonded to a central carbon
atom
– Also bonded to the central carbon is a hydrogen atom
and some other chemical group symbolized by R
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Amino
group
Carboxyl
group
R-groups can have many characteristics
+/-, hydrophobic/hyrophilic, etc.
3.12 Proteins are made from amino acids linked
by peptide bonds
 Amino acid monomers are linked together to form
polymeric proteins
– This is accomplished by an enzyme-mediated
dehydration reaction
– This links the carboxyl group of one amino acid to the
amino group of the next amino acid
– The covalent linkage resulting is called a peptide bond
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Linking amino acids by peptide bonds
• Amino acids are
linked by peptide
bonds
• A polypeptide is a
polymer of amino
acids
• Polypeptides range
in length from a few
to more than a
thousand monomers
Four Levels of Protein Structure
• The primary structure of a protein
is its unique sequence of amino
acids
• Secondary structure
• Tertiary structure is determined by
interactions among various side
chains (R groups)
–
Hydrogen bonds, ionic bonds, hydrophobic
interactions, disulfide bridges may reinforce the
protein’s structure
• Quaternary structure
Tertiary Structure
• The sequence of amino acids determines a
protein’s three-dimensional structure
• A protein’s structure determines its function
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3.12 Denatured proteins change shape
 If a protein changes shape it won’t work as it
should
 Heat
 pH
 Salt concentration
 Chemicals that break H-bonds
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Enzyme B
Rate of
reaction
Enzyme A
0
20
40
60
Temperature (°C)
80
100
3.12 Proteins change shape but they won’t work
the same
 Protein’s shape is changed-it won’t work anymore
 Mutation does not cause a protein to denature, but
can change protein’s shape
plaques
tangles
Diseased vs. normal
 Alzheimer's plaques and tangles in the brain can be caused
from mutations that change the protein’s shape
LIPIDS
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3.8 Fats are lipids that are mostly energy-storage
molecules
 Lipids are water insoluble (hydrophobic, or
water fearing) compounds that are important in
energy storage
– They contain twice as much energy as a polysaccharide
 Fats are lipids made from glycerol and fatty acids
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3.8 Fats are lipids that are mostly energy-storage
molecules
 Fatty acids link to glycerol by a dehydration
reaction
– A fat contains one glycerol linked to three fatty acids
– Fats are often called triglycerides because of their
structure
– Fats are just carbohydrates/sugars converted to a more
energy efficient way of storing calories
Animation: Fats
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• Fatty acids vary in length (number of carbons)
and in the number and locations of double
bonds
• Saturated fatty acids have the maximum
number of hydrogen atoms possible and no
double bonds
• Unsaturated fatty acids have one or more
double bonds
– Their capacity to bond with H atoms is not
saturated, hence unsaturated fatty acids
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Solid vs liquid
• Fats made from
saturated fatty
acids are called
saturated fats, and
are solid at room
temperature
Remove H to create
a double bond
• Fats made from
unsaturated fatty
acids are called
unsaturated fats or
oils, and are liquid
at room
temperature
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• A diet rich in saturated fats may contribute to
cardiovascular disease through plaque deposits
• Hydrogenation is the process of converting
unsaturated fats to saturated fats by adding
hydrogen
• Hydrogenating vegetable oils also creates
unsaturated fats with trans double bonds
• These trans fats may contribute more than
saturated fats to cardiovascular disease
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Quiz 2
1.
Which element is pivotal to the formation of organic compounds?
2.
What is the main difference between covalent and ionic bonding?
3.
T/F As concentration of H+ ions increases, pH number decreases.
4.
T/F Isomers are organic compounds with the same molecular formula
but different structure.
5.
What is the max. amount of bonds that 1 atom of carbon can form?
6.
Oils can be converted to solids at room temperature by adding
and decreasing the number of double bonds.
7.
Match the polymer to the monomer.
1. Nucleotides
a)
DNA
b)
Carbohydrate
2. Fatty Acids, glycerol
c)
Protein
3. Sugars, monosaccharides
d)
Lipid
4. Amino Acids
NUCLEIC ACIDS
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3.16 Nucleic acids are information-rich polymers
of nucleotides
 DNA (deoxyribonucleic acid) and RNA
(ribonucleic acid) are composed of monomers
called nucleotides
– Nucleotides have three parts
– A five-carbon sugar called ribose in RNA and deoxyribose in
DNA
– A phosphate group
– A nitrogenous base
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Nitrogenous
base
(adenine)
Phosphate
group
Sugar
3.16 Nucleic acids are information-rich polymers
of nucleotides
 DNA nitrogenous bases are adenine (A), thymine
(T), cytosine (C), and guanine (G)
– RNA also has A, C, and G, but instead of T, it has uracil
(U)
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Nucleotide
Sugar-phosphate
backbone
Watson and Crick
Base
pair
X-ray crystallography
Daily Recommended Values
Nutrient
Unit of Measure Daily Values
Total Fat
grams (g)
65
grams (g)
20
Cholesterol
milligrams (mg)
300
Sodium
milligrams (mg)
2400
Potassium
milligrams (mg)
3500
Total
carbohydrate
grams (g)
300
grams (g)
25
grams (g)
50
Saturated
fatty acids
Fiber
Protein
You're the manager of a factory that produces enzyme-washed blue jeans (the
enzymes lighten the color of the denim, giving a "faded" appearance). When the most
recent batch of fabric came out of the enzyme wash, however, the color wasn't light
enough to meet your standards. Your quality control laboratory wants to do some
tests to determine why the wash enzymes didn't perform as expected. What has
happened to your enzyme?
Based on your understanding of enzyme structure, which of the following would you
recommend that they investigate?
 Organic Compounds
 Carbon bonds
 Isomers of Carbon
 Dehydration synthesis / hydrolysis
 Name 4 polymers discussed in chapter
 3 important polymers of glucose

Because water and oil don't mix, water is not very
effective at washing away oily dirt. The ability of