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Chapter 5
The Structure and Function of
Macromolecules
Introductory Terms
Macromolecule = “giant” molecule of
living matter
 Monomer = subunits that serve as the
building blocks of a polymer



Example: Lego block
Polymer = monomers linked together

Example: Lego castle
Macromolecular Reactions


Dehydration
Synthesis:


2 molecules
become
covalently bonded
to each other
through the loss of
water
Hydrolysis:

Water is used to
break up polymers
to monomers
Macromolecular Diversity

Diversity in polymers is due to
differing arrangements of
monomers…
Nearly infinite possibilities…
 Alphabet analogy

Carbohydrates

Structure:
C:H:O in a 1:2:1 Ratio
 Example: C6H12O6


Functions:

Short-term energy storage
• Pasta dinner before the big race, game,
etc.

Structural Support
Carbohydrates

Monosaccharides:



“one sugar”
C:H:O Ratio =
1:2:1
Glucose
(C6H12O6) is a
monosaccharide
Carbohydrates

Disaccharides:



“double sugar”
2 monosaccharides
joined together by a
glycosidic linkage
(covalent bond)
Sucrose = glucose +
fructose
Carbohydrates

Polysaccharides


Polymers in which a few
hundred to a few
thousand
monosaccharides are
linked together
Starch and glycogen are
examples
Carbohydrates

Structural Polysaccharides

Cellulose
• Major component of plant
cell walls
• Cannot be digested by
humans
• Fiber!

Chitin
• Used by arthropods to build
exoskeletons
• Cell wall of fungi
Lipids

Structure:
Made up of carbon, hydrogen, oxygen
 Do not dissolve in water


Functions:
Long-term energy storage
 Chemical messengers (hormones)
 Insulation
 Waxes

Lipids

Fats



Made of glycerol
and 3 fatty acids
Fatty acid has a
long carbon
skeleton and a
carboxyl group
C-H bonds
responsible for
hydrophobia of
fats
Lipids

Fats

Saturated Fat =
no double bonds
• Saturated with
hydrogen

Unsaturated Fat =
double bonds
• Not saturated with
hydrogen
Lipids

Phospholipids



Have only 2 fatty
acids
Instead of 3rd fatty
acid, they have a
phosphate group
Major component
of cell membrane
Lipids

Steroids


Made up of 4
interconnected
rings
Examples:
• Cholesterol
• Testosterone
• Estrogen
Proteins ***



Most of a cell is made up of proteins
Instrumental in almost everything organisms
do
Structure:



All proteins are created from unique
combinations of 20 different amino acids
C,H,O,N
Major Functions:



Structure
Defense (antibodies)
Enzymes
Proteins

Amino Acids
Amino acids are the monomers of
proteins
 Organic molecules possessing both
carboxyl and amino groups
 20 types of AAs that make up 1000s
of different proteins
 AAs are linked together by peptide
bonds

Amino Acids
Proteins

A protein is one or more polypeptides precisely twisted, folded and
coiled into a molecule of unique shape (3-D)

4 Levels of Protein Structure

Primary Structure
• Unique sequence of AAs
• Example: Tryptophan-leucine-glycine-glycine-lysine-phenylalanine-serine-leucine
• Sickle Cell Anemia
Proteins

Secondary, Tertiary,
Quaternary Structure:


The amino acid chain is
folded into unique
shapes because of
hydrogen-bonding
This gives each protein
a unique shape
Proteins

Denaturation:



When pH, salt
concentration,
temperature, and/or
other environmental
factors are altered,
the protein may
unravel and lose its
shape
Biologically inactive
Structure + function
Nucleic Acids

Structure



Function


Made up of long
chains of
nucleotides
CHNOPS
Carries genetic
material from one
generation to the
next
DNA and RNA