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Campbell Biology: Concepts & Connections, Eighth EditionREECE • TAYLOR • SIMON • DICKEY • HOGAN

Chapter 3

Lecture by Edward J. Zalisko

The Molecules of Cells

© 2015 Pearson Education, Inc.

Introduction



Figure 3.0-2

Chapter 3 Objectives. You will:

Describe why C is the base of all organic compounds

Characterize Carbohydrates

as fuel and structure

Distinguish Lipids by hydrophobic

characteristics

Differentiate Proteins

structure and function

Connect Nucleic Acids organization to hereditary traits

INTRODUCTION TO ORGANIC

COMPOUNDS


3.1 Life’s molecular diversity is based on the properties of carbon

• carbon bonded to

• other carbons and

• atoms of other elements.

• organic compounds.


Draw a carbon atom with valence shell



Figure 3.1a

The four single bonds of carbon point

to the corners of a tetrahedron.

Methyl group

H

H

H

HC

Animation: L-Dopa


Animation: Carbon Skeletons


Animation: Isomers



Figure 3.1b-1

Length: Carbon skeletons vary

in length.

PropaneEthane


Figure 3.1b-2

Butane Isobutane

Branching: Carbon skeletons may

be unbranched or branched.


Figure 3.1b-3

1-Butene 2-Butene

Double bonds: Carbon skeletons may have

double bonds, which can vary in location.

Double bond


Figure 3.1b-4

Cyclohexane Benzene

Rings: Carbon skeletons may be arranged in

rings. (In the abbreviated ring structures, each

corner represents a carbon and its attached

hydrogens.)


Figure 3.1b-0

Butane

Length: Carbon skeletons vary

in length.

Propane 1-Butene 2-Butene

Double bonds: Carbon skeletons may have

double bonds, which can vary in location.

Double bond

Isobutane Cyclohexane Benzene

Branching: Carbon skeletons may

be unbranched or branched.

Rings: Carbon skeletons may be arranged in

rings. (In the abbreviated ring structures, each

corner represents a carbon and its attached

hydrogens.)

Ethane


Figure 3.2-0

Testosterone Estradiol


Table 3.2-0

3.3

1. carbohydrates,

2. lipids,

3. proteins,

4. nucleic acids.


3.3

• Monomers make polymers

• Polymers make macromolecules


3.3

• Monomers linked through dehydration reactions.

• Polymers broken apart by hydrolysis.

• Mediated by enzymes


Animation: Polymers



Figure 3.3-1-1

Short polymer Unlinked

monomer


Figure 3.3-1-2


monomer

Dehydration reaction

forms a new bond

H2O

Longer polymer


Figure 3.3-2-1


Figure 3.3-2-2

Hydrolysis

breaks a bond

H2O


Figure 3.3-0


monomer

Dehydration reaction

forms a new bond

H2O

Longer polymer

Hydrolysis

breaks a bond

H2O


Figure 3.UN01

Dehydration

Hydrolysis

H2O

H2O

Short polymer Monomer Longer polymer

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.


CARBOHYDRATES


Figure 3.0-2






characteristics




Carbo Hydrate

Carbon Water

C(H2O)

3.4 Monosaccharides are the simplest carbohydrates

• fructose,

• glucose, and

• honey.


Cellular Respiration

• Breakdown glucose to release energy from bonds



Figure 3.4a

Bees with honey, a mixture of two

monosaccharides


Figure 3.4b

Glucose Fructose


Figure 3.4c

Structural

formula

Abbreviated

structure

Simplified

structure

Three representations of the ring

form of glucose

3.5 Two monosaccharides are linked to form a disaccharide

• sucrose is

• a glucose monomer and

• a fructose monomer.

• maltose is

• two glucose monomers.


Animation: Disaccharides



Figure 3.5-1

Glucose Glucose


Figure 3.5-2

Glucose Glucose

Maltose

H2O

3.6 CONNECTION: What is high-fructose corn syrup, and is it to blame for obesity?Page 38

• Summarize:


3.7 Polysaccharides are long chains of monosaccharides

• thousands of monosaccharides.

• storage

• structural compounds.


3.7

• Starch is

• glucose monomers,

• plants energy storage.

• Glycogen is

• glucose monomers,

• animals for energy storage.


3.7

• Cellulose

• glucose monomers

• plant cell walls

• Chitin is

• glucose monomers

• insects and crustaceans exoskeleton

• fungus cell walls.



Figure 3.7-0

Starch granules in

a potato tuber cell Starch

Glycogen granules

in muscle

tissue

Cellulose microfibrils

in a plant cell wall

Cellulose

molecules Hydrogen bonds

Cellulose

Glycogen

Glucose

monomer

3.7

• hydrophilic (water-loving).

• Bath towel made of cotton, which is mostly

cellulose, and therefore water absorbent.


Animation: Polysaccharides



1. Define monosaccharides, disaccharides, and

polysaccharides and explain their functions.


LIPIDS


Figure 3.0-2






characteristics




3.8 Fats are lipids that are mostly energy-storage molecules

• Lipids

• hydrophobic, or water-fearing, compounds,

• long-term energy storage,

• contain twice as much energy as a polysaccharide,

and

• consist mainly of carbon and hydrogen atoms

linked by nonpolar covalent bonds.

• No oxygen


3.8

• not huge molecules and

• not built from monomers.

• Lipids vary a great deal in structure and function.


3.8

• three types of lipids:

1. fats,

2. phospholipids, and

3. steroids.


3.8 Fats

• one glycerol linked to three fatty acids.

• Triglycerides

• Energy storage and insulation


Animation: Fats


Figure 3.UN01

Dehydration

Hydrolysis

H2O

H2O



Figure 3.8a

Glycerol

Fatty acid

H2O


Figure 3.8b


Figure 3.8c-0

Saturated fats Unsaturated fats

3.8

• Fats with the maximum number of hydrogens are

called saturated fatty acids.

• Stack together making a solid at room temperature

• Insulation

• Long term storage

• Draw a saturated fatty acid:



Figure 3.8c-1

Saturated fats


Blubber Glove Demonstration

3.8

• Fatty acids with one or more double bonds form

unsaturated fatty acids.

• kinks or bends prevent them from packing together

tightly and are liquid at room temperature.

• Easier access

Draw and unsaturated fatty acid.



Figure 3.8c-2

Unsaturated fats


Why is coconut oil solid?

3.8

• 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.

• Enzymes don’t recognize fatty acid and it can

remain in body undigested



Table 3.9-0

3.10 Phospholipids

• Cell membranes.

• two fatty acids attached to glycerol.



Figure 3.10

Phosphate

group

Glycerol

Hydrophilic heads

Hydrophobic tails

Symbol for phospholipid

Water

Water


Figure 3.8b


Figure 3.10a

Phosphate

group

Glycerol

Hydrophilic heads

Hydrophobic tails

3.10

• hydrophilic heads

• exterior watery environment and

• internal watery part of the cell.

• The hydrophobic tails cluster together away from

water



Figure 3.10b

Hydrophilic heads

Hydrophobic tails

Symbol for phospholipid

Water

Water

3.10 Steroids

• Steroids contain four fused rings.

• Cholesterol

• animal cell membranes and

• starting material

• Steroids

• Hormones



Figure 3.10c

Cholesterol, a steroid

3.10 CONNECTION: Anabolic steroids pose health risks p41

• Anabolic steroids

• synthetic testosterone

• violent mood swings,

• depression,

• liver damage,

• cancer,

• high cholesterol, and

• high blood pressure.



1. Define lipids, phospholipids, and steroids and

explain their functions.

2. Explain how trans fats are formed in food.

Describe the evidence that suggests that eating

trans fats is more unhealthy than consuming

saturated fats.


PROTEINS


Figure 3.0-2






characteristics




3.12 Proteins

• involved in nearly every dynamic function

• very diverse,

• tens of thousands of different proteins,

Composed of differing arrangements of 20 amino

acid monomers.


3.12

• enzymes

• catalysts

• regulate chemical reactions within cells

• transport proteins embedded in cell membranes

• antibodies of the immune system,

• many hormones and chemical messengers.


3.12

• receptor proteins on cell membranes,

• contractile proteins in muscle cells,

• structural proteins, collagen

• storage proteins, eggs and seeds.


3.12

• The function depend on shape.

• hundreds or thousands of amino acids

• sequence determines particular shape.



Figure 3.12a

Groove

Ribbon model of the protein

lysozyme


Figure 3.12b

Groove

Space-filling model of the protein

lysozyme


Figure 3.12c

Fibrous silk proteins of a spider’s web

3.12

• denature,

• unravels,

• loses its specific shape, and

• loses its function.

• changes in salt concentration, pH, or high heat.



Figure 3.13a

Amino

group

Carboxyl

group


Figure 3.13b

Hydrophobic Hydrophilic

Leucine (Leu) Serine (Ser) Aspartic acid (Asp)


Figure 3.UN01

Dehydration

Hydrolysis

H2O

H2O



Figure 3.13c-1

Carboxyl

group

Amino

group

Amino acid Amino acid


Figure 3.13c-2

Carboxyl

group

Amino

group

Amino acid

Dehydration

reaction

Peptide bond

Dipeptide

H2O

Amino acid

four levels of structure

1. primary structure,

2. secondary structure,

3. tertiary structure, and

4. quaternary structure.


Animation: Protein Structure Introduction


Animation: Primary Protein Structure


Animation: Secondary Protein Structure


Animation: Tertiary Protein Structure


Animation: Quaternary Protein Structure



Figure 3.14-0

Amino

acids

+H3N

Amino end

Peptide bondsconnect aminoacids.

Alpha

helix

Secondary structuresare maintained byhydrogen bondsbetween atoms

of thebackbone.

Beta pleated sheet

Tertiary structure isstabilized by interactionsbetween R groups.

TERTIARY STRUCTURE

PRIMARY STRUCTURE

Two types of

SECONDARY STRUCTURES

Polypeptides are associated

into a functional protein.

QUATERNARY

STRUCTURE


Figure 3.14-1

Amino

acids

+H3N

Amino end


PRIMARY

STRUCTURE


Figure 3.14-2

Alpha

helix


of thebackbone.

Beta pleated sheet

Two types of

SECONDARY

STRUCTURES


Figure 3.14-0-2

Amino

acids

+H3N

Amino end


Alpha

helix


of thebackbone.

Beta pleated sheet

PRIMARY STRUCTURE

Two types of



Figure 3.14-3

Tertiary structure is stabilized by interactionsbetween R groups.

TERTIARY STRUCTURE


Figure 3.14-0-3

Amino

acids

+H3N

Amino end


Alpha

helix


of thebackbone.

Beta pleated sheet


TERTIARY STRUCTURE

PRIMARY STRUCTURE

Two types of



Figure 3.14-4



QUATERNARY

STRUCTURE


Figure 3.14-0-4

Amino

acids

+H3N

Amino end


Alpha

helix


of thebackbone.

Beta pleated sheet




TERTIARY STRUCTURE

PRIMARY STRUCTURE

QUATERNARY

STRUCTURE

Two types of


Cook egg with acid demonstration


Sickle Cell


6. Describe the chemical structure of proteins and

the importance of proteins to cells.


NUCLEIC ACIDS


Figure 3.0-2






characteristics




3.15 DNA

• Genes consist of DNA (deoxyribonucleic acid), a

type of nucleic acid.

• inherited from parents.

• directions for its own replication.

• directs the synthesis of proteins.


3.15 RNA

• RNA (ribonucleic acid).

• DNA is transcribed into RNA

• RNA is translated into proteins

•Central Dogma



Figure 3.15-1

Gene

DNA


Figure 3.15-2

Gene

Transcription

DNA

RNA

Nucleic acids


Figure 3.15-3

Gene

Transcription

Translation

Amino

acid

DNA

RNA

Protein

Nucleic acids

3.16

• monomers called nucleotides.

1. a five-carbon sugar

2. a phosphate group, and

3. a nitrogenous base.


Figure 3.UN01

Dehydration

Hydrolysis

H2O

H2O



Figure 3.16a

Sugar

Phosphate

group

Nitrogenous

base

(adenine)

3.16 nitrogenous bases

• DNA

• adenine (A),

• thymine (T),

• cytosine (C),

• guanine (G).

• RNA.

• adenine (A),

• uracil (U),

• cytosine (C),

• guanine (G).



Figure 3.16b

Nucleotide

Sugar-phosphate

backbone

A

T

C

G

T

3.16 Nucleic acids are polymers of nucleotides

• RNA is a single strand.

• DNA is a double helix,



Figure 3.16c

Base

pair

C G

C G

C G

CG

T A

T A

TA

TA

TA

TA

3.16 EVOLUTION CONNECTION: Lactose tolerance is a recent event in human evolution page 47

• Summarize:



Figure 3.17


6. Describe the chemical structure of nucleic acids

and explain how they relate to inheritance.

7. Explain how lactose tolerance has evolved in

humans.



Figure 3.UN02-0


Figure 3.UN02-1


Figure 3.UN02-2


Figure 3.UN03

Testing your knowledge, question 17


Figure 3.UN04

Sucrose



Figure 3.UN06

Enzyme A Enzyme B

Temperature (C)

Rate

of

reacti

on

0 20 40 60 80 100


Clicker Questions for

Campbell Biology: Concepts & Connections, Eighth EditionREECE • TAYLOR • SIMON • DICKEY • HOGAN

Chapter 3

Updated by Shannon Datwyler

The Molecules of Cells


Concept Check

The formation of starch from simple sugars such as glucose

involves a series of _______________ reactions.

a) hydrolysis

b) dehydration

c) hydrophobic

d) denaturation


Answer

The formation of starch from simple sugars such as glucose

involves a series of _______________ reactions.

a) hydrolysis

b) dehydration

c) hydrophobic

d) denaturation


Concept Check

The primary structure of a protein is determined by

a) The interaction of the R-groups on each of the amino acids.

b) The way in which the peptide bond forms.

c) The sequence of amino acids in the polypeptide chain.

d) Hydrogen bonds formed on the polypeptide backbone.


Answer

The primary structure of a protein is determined by

a) The interaction of the R-groups on each of the amino acids.

b) The way in which the peptide bond forms.

c) The sequence of amino acids in the polypeptide chain.

d) Hydrogen bonds formed on the polypeptide backbone.


Concept Check

When proteins are heated, they

usually denature. If moderate heat

was applied to this molecule of

DNA, which part of the molecule

would break down or break apart

first? (Use your knowledge of

chemical bonds.)

a) The nucleotides along each

side would break apart.

b) The sugar-phosphate backbone

would separate from the

nitrogen bases.

c) The nitrogen base pairs would

separate in the interior of the

molecule.© 2015 Pearson Education, Inc.

Answer

When proteins are heated, they

usually denature. If moderate heat

was applied to this molecule of

DNA, which part of the molecule

would break down or break apart

first? (Use your knowledge of

chemical bonds.)

a) The nucleotides along each

side would break apart.

b) The sugar-phosphate backbone

would separate from the

nitrogen bases.

c) The nitrogen base pairs would

separate in the interior of the

molecule.© 2015 Pearson Education, Inc.

Concept Check

The amino acid R-groups interact to create the three-dimensional

structures of proteins. Some amino acids have hydrophilic side

groups, while others have hydrophobic side groups. In the

hydrophilic group, some “R” groups are acids and others are bases.

What type(s) of amino acids are acidic R-groups most likely to

interact with?

a) Hydrophobic amino acids

b) Acidic amino acids

c) Basic amino acids

d) All of the above


Answer

The amino acid R-groups interact to create the three-dimensional

structures of proteins. Some amino acids have hydrophilic side

groups, while others have hydrophobic side groups. In the

hydrophilic group, some “R” groups are acids and others are bases.

What type(s) of amino acids are acidic R-groups most likely to

interact with?

a) Hydrophobic amino acids

b) Acidic amino acids

c) Basic amino acids

d) All of the above


Concept Check

The key to a protein’s function is its shape. The shape can be

altered (or denatured) under unfavorable conditions. By heating a

protein such as that found in egg whites, the protein’s shape

changes. What best describes why this happens?

a) Interactions between R-groups change, resulting in a change in

the secondary structure of the protein.

b) Peptide bonds undergo a series of dehydration reactions.

c) Peptide bonds undergo a series of hydrolysis reactions.


Answer

The key to a protein’s function is its shape. The shape can be

altered (or denatured) under unfavorable conditions. By heating a

protein such as that found in egg whites, the protein’s shape

changes. What best describes why this happens?

a) Interactions between R-groups change, resulting in a change in

the secondary structure of the protein.

b) Peptide bonds undergo a series of dehydration reactions.

c) Peptide bonds undergo a series of hydrolysis reactions.


Science and Society

Seeking to gain an edge over

the competition, some athletes

have turned to anabolic steroids

to enhance their performance.

Due in part to the negative

health effects of steroid use,

most sports organizations ban

the use of steroids.

Do you believe that sports

organizations should ban the

use of performance-

enhancing drugs?


Disagree Agree

Strongly A B C D E Strongly

Science and Society

Olympic track and field records

appear to have leveled off and

perhaps even declined from a

high point in the early to mid-

1990s. Some have suggested

that many of the records set

during this time period were due

to drug-based enhancement.

Should these records be

thrown out?


Disagree Agree

Strongly A B C D E Strongly

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