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.

1

• 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.

2

• 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.

3

• What is one way that polymers can be classified?

Polymers can be classified as natural polymers or
synthetic polymers.
4

• 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.

5
Synthetic Polymers

• What are three examples of synthetic polymers?

Rubber, nylon, and polyethylene are three
examples of compounds that can be synthesized.
6
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.

7
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.

8
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
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.

10
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.
11
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.

12
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.

13
Natural Polymers

• All the foods shown contain starch, which is a
  polymer of the simple sugar glucose.

14
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.

15
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.

16
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.

17
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.

18
Natural Polymers
19
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.

20
Natural Polymers

• There are about 20 amino acids that your body
  needs to function. They include glycine and
  phenylalanine.

21
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.

22
Natural Polymers

• These foods are all good protein sources.

23
Assessment Questions

• A synthetic polymer that can be formed into
  strong fibers suitable for making cloth and rope
  is
• silk.
• high-density polyethylene.
• natural rubber.
• nylon.

24
Assessment Questions

• A synthetic polymer that can be formed into
  strong fibers suitable for making cloth and rope
  is
• silk.
• high-density polyethylene.
• natural rubber.
• nylon.ANS D

25
Assessment Questions

• The strong natural fiber, cellulose, is a polymer
  made of long chains of what type of molecule?
• amino acid
• organic bases
• hydrocarbons
• sugar

26
Assessment Questions

• The strong natural fiber, cellulose, is a polymer
  made of long chains of what type of molecule?
• amino acid
• organic bases
• hydrocarbons
• sugar
• ANS D

27
Assessment Questions

• A large molecule that forms when many smaller
  molecules are linked together by covalent bonds
  is a monomer. TrueFalse

28
Assessment Questions

• A large molecule that forms when many smaller
  molecules are linked together by covalent bonds
  is a monomer. TrueFalse
• ANS F, polymer