Molecules of Life
Carbs, Proteins, Lipids and Nucleic
Acids
Carbohydrates
• Carbohydrates are better
known as sugars
• These supply organisms
with energy and
structural support
• They come from a variety
of sources and come in a
variety of shapes and
sizes
• They are polymers that
come in repeating units
Carbohydrates
• Monosaccharides are
single units of sugar
– Saccar is Greek for sugar
• Disaccharides are two
monosaccharides
joined together
• Polysaccharides are
three or more
monosaccharides put
together
Carbohydrates
• Monosaccharides are
generally have
molecular formulas that
are similar to glucose
C6H12O6
• They also have two
other trademarks of a
sugar
– Hydroxyl Groups
– A carbonyl group
Carbohydrates
• Most common
monosaccharides form in
rings
• This is a structurally more
stable arrangement
• Common
monosaccharides are
glucose and fructose
• Some common
disaccharides are maltose
and lactose
Carbohydrates
• Polysaccharides do
many different
functions and can be
thousands of
monomers long
• Some common ones are
starch, cellulose and
chitin
Table
Name
Carbohydrates
Monomer
Polymer
monosaccharide polysaccharide
Function
Calories/Gram
Energy and
structural
4 k/g
Proteins
• Proteins are polymers
that contain on of 20
amino acids
• Amino acids are
compounds that
contain three major
things held together by
a central carbon
– Amino Group
– Carboxyl Group
– An R’ group
Proteins
• Amino acids link
together to create a
larger segment called a
linear polypeptide
• They link together by a
dehydration reaction
• Once linked they have a
specific type of bond
called a peptide bond
Proteins
• When multiple amino
acids come together
they can bend, twist
and turn to be
structurally stable
• The molecule will twist
based on what amino
acid sequence is in the
protein
Proteins
• The structure of the
protein determines its
function
• The specific shape
makes the protein fit in
to receptors or enzymes
Proteins
• Protein functions
include
• Structure
• Signaling
• Enzymes (biological
catalysts)
• Energy
Table
Name
Carbohydrates
Proteins
Monomer
Polymer
monosaccharide polysaccharide
Amino acids
Polypeptides/
Proteins
Function
Calories/Gram
Energy and
structural
4 k/g
Structural,
Signaling,
Enzymes,
Energy
4 k/g
Lipids
• Lipids are diverse
compounds that are
grouped together
because they do not mix
with water
• You can see this in any
bottle of salad dressing
where the oil does not
mix with the vinegar
• Lipids do not follow the
typical monomer and
polymer
Lipids
• One major type of lipid is a
fat
• Fats are large molecules
made from smaller
molecules, glycerol and
fatty acids
• A glycerol is a three carbon
alcohol
• A triglyceride is a glycerol
that has three carbon
chains attached to it
• A fatty acid is a long
hydrocarbon chain with a
carboxyl group attached
Lipids
• Some fatty acids have
double bonds and some
do not
• Fatty acids with no
double bonds are
considered saturated
fatty acids
• Fatty acids with one or
more double bonds are
considered unsaturated
fatty acids
Lipids
• Fats have the function
of long term energy
storage
• Carbohydrates and
proteins contain 4
calories/gram of energy
• Fats contain 9
calories/gram of energy
Lipids
• Phospholipids are
similar to fats, but they
contain only two fatty
acid chains
• This makes the “head” a
slightly different charge
than the “tail”
• These form in double
layers that wrap around
the cell
Lipids
• Steroids are lipids in
which the carbon
skeleton contains four
fused rings
• Cholesterol is a type of
steroid
• Waxes are a different
type of lipid that have
long chains of carbons
Table
Name
Carbohydrates
Proteins
Lipids
Monomer
Polymer
monosaccharide polysaccharide
Amino acids
Polypeptides/
Proteins
Function
Calories/Gram
Energy and
structural
4 k/g
Structural,
Signaling,
Enzymes,
Energy
4 k/g
Long term
energy storage
9 k/g
Nucleic Acids
• Nucleic acids are long
chains of repeating
molecules
• DNA (deoxyribonucleic
acid) and RNA
(ribonucleic acid) are
the two types
• These both are used to
store and send
information
Nucleic Acids
• Nucleic acids have
monomers called
nucleotides
• A nucleotide is a
molecule that contains
a phosphate group, a
sugar and a nitrogenous
base
• The nitrogen base can
be different from
nucleotide to
nucleotide
Nucleic Acids
• Nucleotides fit together
to form a long chain
polymer
• DNA forms a double
helix
• RNA forms a single helix
Table
Name
Carbohydrates
Monomer
Polymer
monosaccharide polysaccharide
Lipids
Function
Calories/Gram
Energy and
structural
4 k/g
Long term
energy storage
9 k/g
4 k/g
Proteins
Amino acids
Polypeptides/
Proteins
Structural,
Signaling,
Enzymes,
Energy
Nucleic Acids
nucleotide
DNA/RNA
Information
Storage