Organic Molecules
Biochemistry
Organic Molecule
• Is a hydrocarbon
• Carbon bonds to
hydrogen
• Simplest hydrocarbon
is when 4 hydrogen
atoms bond to one
carbon (methane)
• CH4
A Little Less Simple
• Carbon binds to other
carbon atoms
• This is the uniqueness
of carbon: it can bind
to itself
• Ethane is C2H6
A Little More Less Simple
• Carbon likes to form
long chains
• Pentane: 5 carbons
• C5H12
A Little More Complicated
• Branched chains
• Isohexane
• C6H14
A Lot More Complicated
• Form rings
• C6H12
• Cyclohexane
Even More
Complicated
• Carbon-Carbon single
bonds
• Carbon-Carbon double
bonds
• Carbon-Carbon triple
bonds
• As you increase the
number of bonds between
carbons, the number of
hydrogen atoms decreases
How many single vs double
bonds?
These are Alkanes
• Determines saturated
or unsaturated
• Have special names
• Saturated has only
single bonds—every
carbon is bonded
singly to another
carbon and hydrogen
occupies every other
spot
Alkenes
• Unsaturated
• Contain one or more
double bonds between
carbon atoms
• Not EVERY possible
spot is occupied by a
hydrogen
Alkynes
Ethyne
• Contain a triple bond
• Fewer hydrogen atoms
Living Things
• Simple hydrocarbons not common in living
organisms
• They form the building blocks of more
complex organic molecules that make up
living organisms
Four Categories
Based on function
• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids
All four have in common…
• Carbon backbone
• Other atoms, usually
H,O,N,P,and/or S
• These atoms form
functional groups, which
we can recognize
• These groups replace the
H that would be in a
typical hydrocarbon
In common…
• all form by
dehydration synthesis
• This means single
units (monomers) join
together; water is
removed to join them
• No polymers in lipids
• Enzyme catalyzed
Dehydration Synthesis
Functional groups give
characteristics
• Attaching the
functional groups to
the carbon backbone
gives the chemical
characteristics of the
organic molecule
• Methane gas vs.
methanol liquid
Methanol
Functional groups
• Formaldehyde has a
strong odor, highly
reactive
• Formic Acid, only
slightly different—
why an acid?
Hydrocarbons
• Only have H attached
to carbon backbone
• Do not break easily
• Very stable
Carbohydrates
Sugars and
Starches
#1 Energy Source
(quick)
Characteristic of Carbohydrates
• A 2 to 1 ratios of
Hydrogen to Oxygen
• C6H12O6
• The basic monomer
(or building block)
is the
monosaccharide
Building Chains
•
•
•
•
•
Two monosaccharides is a disaccharide
Many is a polysaccharide
A few is an oligosaccharide
The simple chains are sugars
The longer chains are starches
Starches
Sugars
• Consists of three or
more C atoms with
either an aldehyde or a
ketone group
• And at least 2 OH
groups
• Formed by
dehydration synthesis
Simple Sugars
• Like to form ring
formations
• Glucose, galactose,
fructose all have the
same molecular
formula
• Different
arrangements
Starch: the main polysaccharide
• Other polysaccharides
include glycogen
(storage in animals)
• Cellulose (plant
material
• Pectin (plant material)
• Starch (storage in
plants)
Lipids
Characteristics
•
•
•
•
•
•
Do not dissolve in water
Hydrophobic
Greasy or oily
Energy Storage
Structural components (esp membranes)
Cannot polymerize
Energy Efficient
• Number one method
of energy storage
• Long term
• Can store twice as
much energy as
carbohydrates
• Due to high number of
C-H bonds—very
energy efficient
Common Types
• Triglycerides: one
glycerol and three
fatty acids (70 types)
• Fat is solid at room
temperature
(saturated)
• Oils are liquid
(unsaturated)
Saturated vs Unsaturated
• Saturated: contains a
H at every possible
location on the fatty
acids
• Unsaturated: contains
one or more double
bonds
Saturated
Phospholipids
• Split personality
• A glycerol and two fatty
acids
• A phosphate group takes
the place of the third fatty
acid
• Glycerol is hydrophobic
• Phosphate is hydrophyllic
Phospholipids
Phospholipids
Sterols (Steroids)
• No fatty acid tails
• All have backbone of
4 fused carbon rings
with functional groups
• Hormones and
cholesterol are in this
group
Testosterone
Waxes
• Fatty acids linked to a
long chain with
alcohol
• Hydrophobic
• Waterproof covering
for insects, leaves,
skin on fruit
Proteins
Proteins
• Most diverse group
• Many functions
• Shape determines
function
• Functions include:
structural, hormones,
enzymes
• Monomer is the amino
acid
Each amino acid has
• One carbon with 4
groups attached
• The 4 groups are:
amine group NH2
• Carboxyl group
COOH
• Hydrogen
• R group—varies with
each amino acid
Amino Acids
• The R group is what
gives each amino acid
its physical and
chemical properties
• It does this by shape
and the fact that the R
group can be polar or
nonpolar; acidic or
basic
Making protein chains
• The more amino acids
in the chain, the more
complex the protein
• The amine group from
one joins to the
carboxyl end of the
other
• This is known as a
peptide bond
Protein Structure
Proteins have a 3D
shape
Four factors contribute
to the shape: primary
structure, secondary
structure, tertiary
structure, and
quaternary structure
Primary Structure
• This is the amino acid
sequence.
• There are 20 different
amino acids
• Which ones, and in
what order,
determines the
primary structure
Secondary Structure
• Strand folds or coils
• Caused by hydrogen
bonds between non
adjacent amino acids
Tertiary Structure
• Actual 3D shape
• Bends and loops into a
glob as R groups react
with other R groups
Quaternary Structure
• Two or more
polypeptide chains
have joined together
by numerous weak
hydrogen bonds and/or
covalent bonds
between R groups