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Marvelous
Macromolecules
Chapter 5
Macromolecules
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Large molecules formed by joining
smaller organic molecules
Four Major Classes
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Carbohydrates
Lipids
Proteins
Nucleic Acids
Polymers
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Many similar or identical building
blocks linked by covalent bonds
Monomers
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Small units that join together to make
polymers
Connected by covalent bonds using a
condensation (dehydration) reaction
One monomer gives a hydroxyl group,
the other gives a hydrogen to form
water
Process requires ENERGY and
ENZYMES
Let’s Get Together…
Yah, Yah, Yah
Breakdown
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Polymers are disassembled by
hydrolysis
The covalent bond between the
monomers is broken splitting the
hydrogen atom from the hydroxyl
group
Example – digestion breaks down
polymers in your food into monomers
your body can use
Breakin’ Up is Hard to Do…
Variety
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Each cell has thousands of different
macromolecules
These vary among cells of the same
individual; they vary more among
unrelated individuals in the same
species; and vary even more in different
species
40 to 50 monomers combine to make the
huge variety of polymers
Carbohydrates 
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Used for fuel (energy) and building
material
Includes sugars and their polymers
Monosaccharides – simple sugars
Disaccharides – double sugars (two
monosaccharides joined by
condensation reaction
Polysaccharides – polymers of
monosaccharides (many sugars joined
together)
Monosaccharides
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Molecular formula is usually a
multiple of CH2O
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Ex – Glucose C6H12O6
Classification of
Monosaccharides
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ALWAYS HAVE A CARBONYL GRP. and
HYDROXYL GRPS.
Location of carbonyl group
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If carbonyl is on end – aldose
If carbonyl is in middle – ketose
Number of carbons in backbone
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Six carbons – hexose
Five carbons - pentose
Three carbons - triose
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Characteristics of
Monosaccharides
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Major fuel for cellular work –
especially glucose – makes ATP
In aqueous solutions – form rings
Joined by glycosidic linkage
through a dehydration reaction
Disaccharides
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Two monosaccharides joined
together with a glycosidic linkage
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Maltose – formed when 2 glucose
molecules are joined
Sucrose (table sugar) formed by
joining glucose and fructose
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Used to transport sugar in plants
Polysaccharides
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Polymers of sugar
Can be hundreds to thousands of
monosaccharides joined together
by glycosidic linkages
Used in energy storage then
broken down as needed in the cell
Also used to maintain structure in
cells
Examples of Polysaccharides
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Starch – storage polysaccharide
made entirely of glucose
monomers
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Plants store starch in plastids
Plants can use glucose stored in
starch when they need energy or
carbon
When animals eat plants, they use the
starch as an energy source
Made of ALPHA glucose rings
Examples of Polysaccharides
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Cellulose
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Polymer of glucose monomers
Made of BETA glucose rings
Found in Cell Walls of plants (very tough)
Animals can’t digest cellulose (passes
through making digestion easier)
Herbivores have special microbes in their
stomachs that can digest cellulose (that’s
why they can survive on only plants)
Examples of Polysaccharides
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Glycogen – polysaccharide of
glucose used for sugar storage in
ANIMALS
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Humans and vertebrates store
glycogen in liver and muscles
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Examples of Polysaccharides
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Chitin
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Structural polysaccharide
Used in exoskeletons of arthropods
(insects, spiders, crustaceans)
Forms the structural support for cell
walls of fungi
I crunch when I get
stepped on because of
Chitin
Lipids 
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Hydrophobic molecules
Nonpolar bonds making them have
little or no affinity for water
Store large amounts of energy
Not “polymers”, but are large
molecules made from smaller ones
Fats
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Made of glycerol (3 Carbons with
hydroxyl attached) and 3 fatty
acids (long carbon skeleton)
Joined by ester linkage in
dehydration reaction
Used in energy storage, cushion
organs, and for insulation
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Saturated Fats
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Fatty acids with no carbon-carbon
double bonds
Pack tightly together making
SOLIDS at room temperature
Most animal fats are saturated
Eating too much can block arteries
Unsaturated Fats
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Fatty acid has one or more carboncarbon double bonds
Kinks from double bonds prevent tight
packing
Liquid at room temperature
Plant and fish fats - oils
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Phospholipids
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Glycerol joins with 2 fatty acids and 1
phosphate group
Phosphate group carries negative
charge making heads that are
hydrophilic
Fatty acids are nonpolar, making tails
that are hydrophobic
Major components of cell membranes –
phospholipid bilayer
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Steroids
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Carbon skeleton with four fused
carbon rings
Functional groups attached to
rings make different steroids
Cholesterol – used in animal cell
membranes
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Precursor for all other steroids
Many hormones are steroids
Proteins 
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Function in
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Storage
Transport
Intercellular signals
Movement
Defense
Structural Support
Speeding up reactions (enzymes)
Polypeptide
Polymer of amino acids
(monomer) joined by peptide
bonds
 One or more polypeptides come
together to make protein
 Each protein has complex 3-D
Amino Acid
shape
Amino
Acid
Amino Acid
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Amino Acids
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Made of
 Hydrogen
 Carboxyl group
 Amino group
 R-group – varies from one amino acid to the
next
20 amino acid monomers make thousands of
proteins
Joined together by dehydration reaction that
removes hydroxyl group from one and amino
group of another to make a peptide bond
Structure determines
function
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Polypeptides must be folded into a
unique shape before becoming proteins
Order of amino acids determines shape
Shape of protein determines its
function
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Ex. – antibodies bind to foreign substances
based on shape
Folding occurs spontaneously
Levels of Protein
Structure
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Primary – determined by unique
sequence of amino acids
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Order of amino acids comes from
DNA
Changing primary structure can
change the shape of a protein and
could cause it to be inactive
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Ex – sickle cell caused by one amino acid
change
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Levels of Protein
Structure
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Secondary – comes from hydrogen
bonds at regular intervals along
the polypeptide backbone
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Alpha helix – coils
Beta pleated sheets - folds
Levels of Protein
Structure
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Tertiary – determined by interactions
among R-groups on amino acids
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Hydrogen bonds
Hydrophobic/hydrophilic interactions
Van der Waals interactions
Ionic bonds (charged R groups)
Disulfide bridges between sulfhydryl
groups of cysteine amino acids (stabilize
structure)
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Levels of Protein
Structure
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Quaternary – occurs with two or
more polypeptide subunits
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Collagen – three polypeptides coiled
like a rope – good for structure
Hemoglobin – four polypeptide (two
different types) – carries oxygen
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Changing Protein
Structure
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Physical and Chemical conditions can
change the shape of a protein
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pH
Salt concentration
Temperature
Others
Changes can disrupt secondary or
tertiary structures
Some proteins can return to original
shape, but others are permanently
denatured
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Nucleic Acids 
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Polymers formed by joining Nucleotide
monomers with phosphodiester linkages
Store and transmit hereditary information
Inherited from one cell to the next during
cell division
Program the primary structure of proteins
through instructions in the genes of DNA
Information travels from
DNAmRNAprotein
Examples – DNA, RNA, ATP
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Nucleotides
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Made of 3 parts
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Pentose sugar (usually deoxyribose or
ribose)
Phosphate group
Nitrogen Base
Backbone – sugar and phosphate
(phosphodiester link)
Steps – Nitrogen base
Make a Double Helix
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Nitrogen Bases
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Rings of Carbon and nitrogen
Purines – two rings
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Pyrimidines – one ring
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Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
Uracil (U)
A always pairs with T, C pairs with G in DNA
Bases are connected in middle of ladder by
HYDROGEN BONDS 
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Polynucleotides
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Connect Sugar of one nucleotide to
phosphate of next making a backbone
Nitrogen bases in the middle vary from
one organism to the next creating a
unique sequence of DNA
DNA creates proteins in cells therefore
different organisms create different
proteins based on the order of bases in
DNA