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CAMPBELL BIOLOGY: CONCEPTS & CONNECTIONS, NINTH EDITION
PowerPoint Lectures
Chapter 3
The Molecules of Cells
TAYLOR
SIMON
DICKEY
HOGAN
REECE
© 2018 Pearson Education, Inc.
Lecture by Edward J. Zalisko
Introduction
• Most of the world’s population cannot digest milkbased foods.
• These people are lactose intolerant, because they
lack the enzyme lactase.
• This illustrates the importance of biological
molecules, such as lactase, in the daily functions of
living organisms.
© 2018 Pearson Education, Inc.
Figure 3.0_1
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Figure 3.0_2
Chapter 3: Big ldeas
Introduction to Organic
Compounds
Lipids
© 2018 Pearson Education, Inc.
Carbohydrates
Proteins
Nucleic Acids
INTRODUCTION TO ORGANIC COMPOUNDS
© 2018 Pearson Education, Inc.
3.1 Life’s molecular diversity is based on the
properties of carbon
• Carbon’s ability to bond with four other atoms is
the basis for building large and diverse organic
compounds.
• Carbon chains form the backbone of most organic
molecules.
• Isomers have the same molecular formula but
different structures.
• Hydrocarbons are composed of only carbon and
hydrogen.
© 2018 Pearson Education, Inc.
3.1 Life’s molecular diversity is based on the
properties of carbon
Checkpoint question Methamphetamine occurs as
two isomers: one is the addictive illegal drug
known as “crank”; the other is a sinus medication.
How can you explain these differing effects?
© 2018 Pearson Education, Inc.
Figure 3.1b
Double bond
Ethane
Propane
Length: Carbon skeletons
vary in length.
Butane
Isobutane
Branching: Carbon skeletons
may be unbranched or
branched.
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1-Butene
2-Butene
Double bonds: Carbon skeletons may
have double bonds, which can vary in
location.
Cyclohexane
Benzene
Rings: Carbon skeletons may be arranged
in rings. (In the abbreviated ring structures,
each corner represents a carbon and its
attached hydrogens.)
Animation: Carbon Skeletons
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Animation: Isomers 2
© 2018 Pearson Education, Inc.
Animation: Isomers
© 2018 Pearson Education, Inc.
3.2 A few chemical groups are key to the
functioning of biological molecules
• An organic compound’s properties depend on the
• size and shape of its carbon backbone and
• atoms attached to that skeleton.
• Hydrophilic functional groups give organic
molecules specific chemical properties.
• Table 3.2 illustrates six important chemical groups.
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Checkpoint question Identify the chemical groups
that do not contain carbon.
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3.2 A few chemical groups are key to the functioning of
biological molecules
• The sex hormones
testosterone and
estradiol (a type of
estrogen) differ only
in the groups of
atoms highlighted in
Figure 3.2.
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3.3 Cells make large molecules from a limited
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 or similar building blocks strung
together.
• The building blocks of polymers are called
monomers.
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3.3 Cells make large molecules from a limited
set of small molecules
• Monomers are linked together to form polymers
through dehydration reactions.
• Polymers are broken apart by hydrolysis.
• These reactions are mediated by enzymes.
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Animation: Polymers
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Figure 3.3
OH
Short polymer
OH
H
Unlinked
monomer
Dehydration reaction
forms a new bond
H2O
Hydrolysis
breaks a bond
OH
Longer polymer
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H2O
H
OH
Figure 3.3_1_1
OH
Short polymer
© 2018 Pearson Education, Inc.
H
OH
Unlinked
monomer
Figure 3.3_1_2
OH
Short polymer
OH
Unlinked
monomer
Dehydration reaction
forms a new bond
Longer polymer
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H
H2O
Figure 3.3_2_1
© 2018 Pearson Education, Inc.
Figure 3.3_2_2
H2O
Hydrolysis
breaks a bond
OH
© 2018 Pearson Education, Inc.
H
OH
CARBOHYDRATES
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3.4 Monosaccharides are the simplest
carbohydrates
• Carbohydrates range from small sugar molecules
(monomers) to large polysaccharides.
• Sugar monomers are monosaccharides.
• A monosaccharide has a formula that is a multiple
of CH2O and contains hydroxyl groups and a
carbonyl group.
.
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Figure 3.4b
1
2
3
4
5
6
Glucose
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Fructose
Figure 3.4c
6
5
1
4
2
3
Structural
formula
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Abbreviated
structure
Simplified
structure
3.5 Two monosaccharides are linked to form
a disaccharide
• Two monosaccharides (monomers) can bond to
form a disaccharide in a dehydration reaction.
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Figure 3.5_2
Glucose
Glucose
H 2O
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Maltose
Animation: Disaccharides
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3.7 Polysaccharides are long chains of sugar
units
• Starch and glycogen are storage
polysaccharides.
• Cellulose is structural, found in plant cell walls.
• Chitin is a component of insect exoskeletons and
fungal cell walls.
Checkpoint question Compare and contrast starch
and cellulose, two plant polysaccharides.
© 2018 Pearson Education, Inc.
Figure 3.7
Starch granules in
a potato tuber cell
Starch
Glucose
monomer
Glycogen granules
in muscle
tissue
Cellulose microfibrils
in a plant cell wall
Cellulose
molecules
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Glycogen
Cellulose
Hydrogen bonds
Animation: Polysaccharides
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LIPIDS
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3.8 Fats are lipids that are mostly energystorage molecules
• Lipids are diverse hydrophobic compounds
composed largely of carbon and hydrogen.
• Fats (triglycerides) consist of glycerol linked to
three fatty acids.
• Some fatty acids contain one or more double
bonds, forming unsaturated fatty acids.
Unsaturated fatty acids are typical of plant oils.
• Fats with the maximum number of hydrogens are
called saturated fatty acids. Saturated fatty acids
are found in animal fats.
© 2018 Pearson Education, Inc.
3.8 Fats are lipids that are mostly energystorage molecules
• Hydrogenated vegetable oils are unsaturated fats
that have been converted to saturated fats by
adding hydrogen.
• This hydrogenation creates trans fats, which are
associated with health risks.
Checkpoint question Explain why fats are
hydrophobic.
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Figure 3.8a
Glycerol
H
OH
H2O
Fatty acid
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Figure 3.8b
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Figure 3.8c
Saturated fats
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Unsaturated fats
Figure 3.9
100%
increase
in risk
2.00
1.93
50%
increase
in risk
1.50
Baseline
(no risk
difference)
50%
decrease
in risk
75%
decrease
in risk
© 2018 Pearson Education, Inc.
Trans fat
1.75
1.25
1.17
1.00
Saturated fat
0.81
0.75
0.62
0.50
Monounsaturated fat
0.25
Polyunsaturated fat
Animation: Fats (triglycerides)
© 2018 Pearson Education, Inc.
3.9 SCIENTIFIC THINKING: Scientific studies
document the health risks of trans fats
Checkpoint question What is the difference
between a retrospective and a prospective study?
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3.10 Phospholipids and steroids are
important lipids with a variety of functions
• Phospholipids are components of cell
membranes.
• Steroids include cholesterol and some hormones.
• Cholesterol is a common component in animal
cell membranes and is also the precursor for
making other steroids, including sex hormones.
Checkpoint question Compare the structure of a
phospholipid with that of a fat.
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Figure 3.10a
Phosphate
group
Glycerol
Hydrophilic heads
Hydrophobic tails
Water
Hydrophilic heads
Hydrophobic tails
Symbol for phospholipid
© 2018 Pearson Education, Inc.
PROTEINS
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3.12 Proteins have a wide range of functions
and structures
• Proteins are involved in nearly every dynamic
function in your body and are very diverse.
• Proteins function as
•
•
•
•
•
•
•
•
enzymes,
transport proteins embedded in cell membranes,
defensive proteins, such as antibodies,
signal proteins such as many hormones,
receptor proteins,
contractile proteins found within muscle cells,
structural proteins such as collagen, and
storage proteins.
© 2018 Pearson Education, Inc.
3.12 Proteins have a wide range of functions
and structures
• Proteins are composed of differing arrangements
of a common set of just 20 amino acid
monomers.
• The functions of different types of proteins depend
on their individual shapes.(1o-4o structures)
• In the process of denaturation, a protein unravels,
loses its specific shape, and loses its function.
© 2018 Pearson Education, Inc.
3.13 Proteins are made from amino acids
linked by peptide bonds
• Protein diversity is based on different sequences of
amino acids, monomers that contain
•
•
•
•
an amino group,
a carboxyl group,
an H atom, and
an R group, all attached to a central carbon.
• The R groups distinguish 20 amino acids, each
with specific properties.
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3.13 Proteins are made from amino acids
linked by peptide bonds
• Amino acid monomers are linked together in a
dehydration reaction,
• joining the carboxyl group of one amino acid to the
amino group of the next amino acid, and
• creating a peptide bond.
• Additional amino acids can be added by the same
process to create a chain of amino acids called a
polypeptide.
Checkpoint question By what process do you
digest the proteins you eat into their individual
amino acids?
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Figure 3.13a
Amino
group
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Carboxyl
group
Figure 3.13c_1
Carboxyl
group
Amino acid
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Amino
group
Amino acid
Figure 3.13c_2
Carboxyl
group
Amino acid
© 2018 Pearson Education, Inc.
Amino
group
Amino acid
Peptide bond
Dehydration
reaction
H2O
Dipeptide
3.14 VISUALIZING THE CONCEPT: A protein’s
functional shape results from four levels of
structure
• A protein can have four levels of structure:
1. A protein’s primary structure is the sequence of
amino acids in its polypeptide chain.
2. Its secondary structure is the coiling or folding
of the chain, stabilized by hydrogen bonds.
3. The tertiary structure is the overall threedimensional shape of a polypeptide, resulting
from interactions among R groups.
4. Proteins made of more than one polypeptide have
quaternary structure.
© 2018 Pearson Education, Inc.
3.14 VISUALIZING THE CONCEPT: A protein’s
functional shape results from four levels of
structure
Checkpoint question Why does a denatured
protein no longer function normally?
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Figure 3.14
PRIMARY STRUCTURE
+H N
3
Amino end
Peptide bonds
connect amino acids.
+
Two types of
SECONDARY STRUCTURES
Alpha helix
Secondary structures
Beta pleated sheet
are maintained by
hydrogen bonds
between atoms of
the backbone.
TERTIARY STRUCTURE
Tertiary structure is
stabilized by interactions
between R groups.
QUATERNARY STRUCTURE
Polypeptides are associated
into a functional protein.
© 2018 Pearson Education, Inc.
Animation: Protein Structure Introduction
© 2018 Pearson Education, Inc.
Figure 3.14_1
PRIMARY STRUCTURE
+H N
3
Amino end
Peptide bonds
connect amino acids.
+
© 2018 Pearson Education, Inc.
Animation: Primary Protein Structure
© 2018 Pearson Education, Inc.
Figure 3.14_2
Two types of
SECONDARY STRUCTURES
Alpha helix
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Secondary structures Beta pleated sheet
are maintained by
hydrogen bonds
between atoms of
the backbone.
Animation: Secondary Protein Structure
© 2018 Pearson Education, Inc.
Figure 3.14_3
TERTIARY STRUCTURE
Tertiary structure is stabilized
by interactions between R
groups.
© 2018 Pearson Education, Inc.
Animation: Tertiary Protein Structure
© 2018 Pearson Education, Inc.
Figure 3.14_4
QUATERNARY STRUCTURE
Polypeptides are associated
into a functional protein.
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Animation: Quaternary Protein Structure
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NUCLEIC ACIDS
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3.15 The nucleic acids DNA and RNA are
information-rich polymers of nucleotides
• The monomers that make up nucleic acids are
nucleotides.
• Nucleotides are composed of a sugar, a phosphate
group, and a nitrogenous base.
• DNA is a double helix.
• RNA is a single polynucleotide chain.
• DNA and RNA serve as the blueprints for proteins
and thus control the life of a cell.
• DNA is the molecule of inheritance.
© 2018 Pearson Education, Inc.
Figure 3.15b
A
T
C
G
T
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Sugar-phosphate
backbone
Nucleotide
Figure 3.15c
C
C
G
G
T
A
C
G
A
Base
pair
T
A
T
G
C
A
A
T
© 2018 Pearson Education, Inc.
A
T
T
Figure 3.15a
Nitrogenous
base
(adenine)
Phosphate
group
Sugar
(deoxyribose)
© 2018 Pearson Education, Inc.
Figure 3.15d_1
Gene
DNA
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Figure 3.15d_2
Gene
DNA
Nucleic acids
Transcription
RNA
© 2018 Pearson Education, Inc.
Figure 3.15d_3
Gene
DNA
Nucleic acids
Transcription
RNA
Translation
Protein
Amino
acid
© 2018 Pearson Education, Inc.
You should now be able to
1. Describe the importance of carbon to life’s
molecular diversity.
2. Describe the chemical groups that are important
to life.
3. Explain how a cell can make a variety of large
molecules from a small set of molecules.
4. Define monosaccharides, disaccharides, and
polysaccharides and explain their functions.
5. Define lipids, phospholipids, and steroids and
explain their functions.
© 2018 Pearson Education, Inc.
You should now be able to
6. Explain how trans fats are formed in food.
Describe the evidence that suggests that eating
trans fats is more unhealthy than consuming
saturated fats.
7. Describe the chemical structure of proteins and
the importance of proteins to cells.
8. Describe the chemical structure of nucleic acids
and explain how they relate to inheritance.
9. Explain how lactose tolerance has evolved in
humans.
© 2018 Pearson Education, Inc.
Figure 3.10
Phosphate
group
Glycerol
Water
Hydrophilic heads
Hydrophobic tails
Symbol for phospholipid
Water
© 2018 Pearson Education, Inc.
Table 3.2_1
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Table 3.2_2
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Figure 3.UN01
H 2O
OH
Short polymer
H
Dehydration
H
Monomer
Hydrolysis
H2O
© 2018 Pearson Education, Inc.
H
Longer polymer
Figure 3.UN02
Classes of Molecules
and Their Components
Functions
Examples
Energy for cell,
raw material
a.
b.
Starch, glycogen
Monosaccharide
Plant cell support
c.
Lipids
(don’t form polymers)
Energy storage
d.
e.
Phospholipids
Components of a fat molecule
Hormones
f.
Proteins
g.
j.
k.
l.
Transport
Communication
n.
Storage
Receive signals
Lactase
Hair, tendons
Muscle proteins
m.
Signal proteins
Antibodies
Proteins in seeds
Receptor protein
Heredity
r.
s.
DNA and RNA
Carbohydrates
Glycerol
Fatty acid
h.
i.
Amino acid
Nucleic Acids
p.
o.
Nucleotide q.
© 2018 Pearson Education, Inc.
Figure 3.UN02_1
Classes of Molecules
and Their Components
Functions
Examples
Energy for cell,
raw material
a.
b.
Starch, glycogen
Monosaccharide
Plant cell support
c.
Lipids
(don’t form polymers)
Energy storage
d.
e.
Phospholipids
Hormones
f.
Carbohydrates
Glycerol
Fatty acid
Components of a fat molecule
© 2018 Pearson Education, Inc.
Figure 3.UN02_2
Classes of Molecules
and Their Components
Functions
Examples
i.
Amino acid
j.
k.
l.
Transport
Communication
n.
Storage
Receive signals
Lactase
Hair, tendons
Muscle proteins
m.
Signal proteins
Antibodies
Proteins in seeds
Receptor protein
Nucleic Acids
Heredity
r.
s.
DNA and RNA
Proteins
g.
h.
p.
o.
Nucleotide q.
© 2018 Pearson Education, Inc.
Figure 3.UN03
© 2018 Pearson Education, Inc.
Figure 3.UN04
Sucrose
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Figure 3.UN05
© 2018 Pearson Education, Inc.
Figure 3.UN06
Enzyme B
Rate of
reaction
Enzyme A
0
© 2018 Pearson Education, Inc.
20
40
60
Temperature (ºC)
80
100