9.3 Polymers
Couplers that interlock connect one railroad car to
another. Many cars can be joined together to form a
train, because there are couplers on both ends of a
car.
9.3 Polymers
A polymer is a large molecule that forms when many
smaller molecules are linked together by covalent
bonds.
• The smaller molecules that join together to form a
polymer are monomers.
• In some polymers, there is only one type of monomer.
Other polymers have two or more kinds of monomers.
9.3 Polymers
What is one way that polymers can be
classified?
Polymers can be classified as natural
polymers or synthetic polymers.
9.3 Polymers
Many important types of biological molecules are
natural polymers. Organisms produce these polymers
in their cells.
Synthetic polymers are developed by chemists in
research laboratories and manufactured in factories.
Both types of polymers have industrial uses. Silk and
cotton fabrics are woven from natural polymer fibers,
while polar fleece is made from a synthetic polymer.
9.3 Polymers
Synthetic Polymers
What are three examples of synthetic
polymers?
Rubber, nylon, and polyethylene are three
examples of compounds that can be
synthesized.
9.3 Polymers
Synthetic Polymers
Rubber
• The sap collected from rubber trees in tropical
regions contains rubber.
• Chemists produced a synthetic rubber, using
hydrocarbons from petroleum.
• Natural rubber and synthetic rubbers contain
different monomers and have different
properties.
9.3 Polymers
Synthetic Polymers
Nylon
• Research to make artificial silk led to nylon,
which has properties not found in natural
polymers.
• Nylon fibers are very strong, durable, and shiny.
• Nylon is used in parachutes, windbreakers,
fishing line, carpets, and ropes.
9.3 Polymers
Synthetic Polymers
Polyethylene
Polyethylene forms when ethene (or ethylene)
molecules link head to tail.
The number of carbon atoms in a polyethylene
chain affects the properties of the polymer. The
more carbon atoms in the chain, the harder the
polymer is.
9.3 Polymers
Synthetic Polymers
A Rubber is used to manufacture tires.
B Nylon fibers are strong and do not wear out easily.
C Hard plastic shapes can be made from a
polyethylene polymer.
9.3 Polymers
Natural Polymers
What are four types of polymers that
organisms can produce?
Four types of polymers produced in plant
and animal cells are starches, cellulose,
nucleic acids, and proteins.
9.3 Polymers
Natural Polymers
Starches
Simple sugars have the formula C6H12O6. They can
exist as straight chains or rings. Fructose and
glucose can react to form sucrose (table sugar).
Glucose monomers join to form starches as shown
below.
9.3 Polymers
Natural Polymers
Simple sugars, slightly more complex sugars
such as sucrose, and polymers built from sugar
monomers are all classified as carbohydrates.
Typically, a starch contains hundreds of glucose
monomers. Plants store starches for food and to
build stems, seeds, and roots.
9.3 Polymers
Natural Polymers
All the foods shown
contain starch, which is a
polymer of the simple
sugar glucose.
9.3 Polymers
Natural Polymers
Cellulose
• The carbohydrate cellulose is the main component
of cotton and wood.
• Cellulose molecules contain 3000 or more glucose
monomers.
• Cellulose gives strength to plant stems and tree
trunks.
9.3 Polymers
Natural Polymers
Nucleic Acids
Nucleic acids are large nitrogen-containing
polymers found mainly in the nuclei of cells. There
are two types of nucleic acid, deoxyribonucleic acid
(DNA) and ribonucleic acid (RNA).
Nucleic acids in each cell of a plant or animal store
information about its structures and functions.
9.3 Polymers
Natural Polymers
The monomers in a nucleic acid are nucleotides.
• A DNA nucleotide has three parts: a phosphate
group, deoxyribose sugar, and an organic base.
• When two strands of DNA line up, pairs of bases are
arranged like the rungs of a ladder.
9.3 Polymers
Natural Polymers
The strands in DNA are held together by strong
intermolecular attractions between hydrogen
atoms on one strand and nitrogen or oxygen
atoms on the other strand.
• The strands twist around each other in a structure
called a double helix.
• The order of the base pairs in a strand is a code that
stores information that is used to produce proteins.
9.3 Polymers
Natural Polymers
9.3 Polymers
Natural Polymers
Proteins
Organic acids contain a –COOH group, and organic
bases contains an –NH2 group.
An amino acid is a compound that contains both
carboxyl and amino functional groups in the same
molecule.
9.3 Polymers
Natural Polymers
There are about 20 amino acids that your body
needs to function. They include glycine and
phenylalanine.
9.3 Polymers
Natural Polymers
Your cells use amino acids as the monomers for
constructing protein polymers.
• A protein is a polymer in which at least 100 amino
acid monomers are linked through bonds between
an amino group and a carboxyl group.
• The instructions for making proteins are stored in
DNA.
• Your body may contain as many as 300,000 different
proteins.
9.3 Polymers
Natural Polymers
These foods are all good protein sources.
9.3 Polymers
Assessment Questions
1. A synthetic polymer that can be formed into strong
fibers suitable for making cloth and rope is
a.
b.
c.
d.
silk.
high-density polyethylene.
natural rubber.
nylon.
9.3 Polymers
Assessment Questions
1. A synthetic polymer that can be formed into strong
fibers suitable for making cloth and rope is
a.
b.
c.
d.
silk.
high-density polyethylene.
natural rubber.
nylon.
ANS: D
9.3 Polymers
Assessment Questions
2. The strong natural fiber, cellulose, is a polymer
made of long chains of what type of molecule?
a.
b.
c.
d.
amino acid
organic bases
hydrocarbons
sugar
9.3 Polymers
Assessment Questions
2. The strong natural fiber, cellulose, is a polymer
made of long chains of what type of molecule?
a.
b.
c.
d.
amino acid
organic bases
hydrocarbons
sugar
ANS:
D
9.3 Polymers
Assessment Questions
1. A large molecule that forms when many smaller
molecules are linked together by covalent bonds
is a monomer.
True
False
9.3 Polymers
Assessment Questions
1. A large molecule that forms when many smaller
molecules are linked together by covalent bonds
is a monomer.
True
False
ANS:
F, polymer