

Section 2.3
4 Categories of Organic Molecules
Lipids
Carbohydrates
Fats/Oils/Steroids/Wax
Glucose/Fructose
Starch/Cellulose
Molecules of
Life
Proteins
Biochemicals
Enzymes/Structure/
Movement/Protection
(CHON)
Nucleic Acids
(DNA/RNA)
Organic Compounds
Carbohydrates
Monomer:
Monosaccharide
Lipids
Monomer:
Glycerol and
Fatty Acids
Made up of:
Made up of:
Carbon, Hydrogen,
Oxygen
Carbon, Hydrogen,
Oxygen
(H:O in 2:1 ratio)
(H:O not in 2:1 ratio)
Proteins
Nucleic Acids
Monomer:
Monomer:
Amino Acid
Made up of:
Carbon, Hydrogen,
Oxygen, Nitrogen
Nucleotide
1) 5 Carbon sugar,
2) phosphate group
3)nitrogenous base
Made up of:
Carbon, Hydrogen,
Oxygen, Nitrogen and
Phosphorus
All
compounds are either ORGANIC,
containing carbon bonded to
hydrogen and oxygen, or INORGANIC.
The chemistry of carbon is the
chemistry of life.




>11 million compounds
Contain a C-C or C-H bond in combination with
N, O, S, P or halogens
Simplest = CH4
Most complex = DNA
Allotropes of carbon
Allotropes: Different forms of
an element in same
physical state
Catenation: ability of an
element to form chains
and/or rings of covalently
bonded atoms
Carbon has high bond energies
C-C 346 kJ/mol
C-H 418 kJ/mol

tetrahedral array of C atoms
o sp3 hybridized





high mp (>3500°C)
hardest material known to
man
brittle
most dense (3.5x that of
H2O)
Industrial uses: cutting,
drilling, grinding

layers of hexagonal arrays of
C atoms
o





sp2 hybridized (planar)
high mp
no covalent bonds between
layers – C atoms too far
apart from each other
(London Dispersion forces)
layers slip past one another
lubricant and pencil “lead”
Graphite fibers (stronger
and less dense than steel)sporting goods and aircraft
amorphous form of carbon (no structure)
impure carbon particles resulting from incomplete
combustion


 How
many protons does carbon have? Electrons?
 Carbon has FOUR valence electrons
o Needs eight electrons to be stable
 Carbon
readily forms four covalent bonds with
other atoms, including carbon
 Carbon
can form straight chains, branched
chains, or rings
o Leading to a great variety of organic compounds
Isomers

Isomers – compounds that have the same molecular
formula but different structures
Isomers of C6H14

More C atoms in formula, more isomers
o 18 isomers for C8H18
o 35 isomers for C9H20
o 75 isomers for C10H22
Ex #1) Butane, C4H10
ISOMERS
Ex #2) Butene, C4H8
Ex #3) 2-Butene, C4H8
Ex #4) methyl propene, C4H8
 Indicates
the number and types of atoms
present in a molecule and also shows the
bonding arrangement of the atoms
 One possible isomer of C4H10
 Does
not show 3D shape
 Isomers
in which the atoms are bonded together in
different orders.
 C4H10 (note continuous chain of C atoms)
butane
methylpropane
Melting
Point (°C)
Boiling
Point (°C)
Density at
20°C
-138.4
-0.5
0.5788
-159.4
-11.633
0.549
Butane
Methylpropane
 Only
have carbon and hydrogen
 Simplest organic compounds
 From petroleum (crude oil)
Single Bond
Sharing 2 electrons
A single line
Double Bond
Sharing 4 electrons
Two parallel lines
Triple Bond
Sharing 6 electrons
Three parallel lines
 Organic
PREFIXES
 Indicates the number of carbon atoms in the
hydrocarbon chain

Hydrocarbon: any organic compound that contains
only the elements, hydrogen and carbon
# of C
prefix
# of C
prefix
1
2
MethEth-
6
7
HexHept-
3
4
5
PropButPent-
8
9
10
OctNonDec-
 Prefixes
for alkanes that have 1-4 carbons
are rooted historically.
o These are methane, ethane, propane, and
butane, respectively.
o An easy way to remember the first four names
is the anagram Mary Eats Peanut Butter
(methane, ethane, propane, butane)
 Prefixes
for 5 carbons and up are derived
from the Greek language.
 Organic
SUFFIXES
 Indicates
the types of covalent bonds that are
present in the hydrocarbon chain
o Identifies the series to which it belongs
Formula
determines the
# H atoms
Type of
Bond(s)
-ane
CnH2n+2
Single
Alkene
-ene
CnH2n
Double
Alkyne
-yne
CnH2n-2
Triple
Series
Ending
Alkane
Saturated Hydrocarbons:
compounds that
contain all SINGLE
bonds
Alkanes: each carbon is
bonded to 4 atoms
Only contain single
bonds
– Skeleton: C-C
–
Molecular formula:
CnH2n+2
Compounds that contain at least
one double bond or triple bond
1.
Alkenes: compounds that contain a double
bond
• Skeleton: C=C
•
Molecular formula = CnH2n
2.
Alkynes: compounds that contain a triple
bond
– Skeleton: CC
– Molecular formula = CnH2n-2

To give an alkane a name, a
prefix indicating the number of
carbons in the molecule is added
to the suffix ane
o identifies both the kind of molecule
(an alkane) and how many carbons
the molecule has (the prefix).

The name pentane tells you that
the molecule is an alkane (-ane
ending) and that it has 5 carbons
(pent- indicates 5)
1.
2.
Locate the carbon atoms in the longest carbon chain that
contains the double bond. Use the stem with the ending –ene.
Number the carbon atoms of this chain sequentially,
beginning at the end nearer the double bond. If the
parent chain has more than 3 carbons, insert the number
describing the position of the double bond (indicated
by its 1st carbon location) before the base name.
1-butene
2-butene
http://wps.prenhall.com/wps/media/objects/476/488316/index.html

Named just like the alkenes except the suffix –yne is
added
ethyne
1-butyne
propyne
2-butyne
methane
1-pentene
propyne
2-butyne
nonane
3-hexene
2-pentene
1.
2.
3.
4.
5.
ethene
heptane
3-decyne
butane
2-octene
 An
atom or group of atoms, that
replaces hydrogen in an organic
compound and that defines the
structure of a family of
compounds and determines the
properties of the family.

FUNCTIONAL GROUP - a cluster of atoms that influence
the properties of the molecules that they compose, and
determine the characteristics of the compound.
Lactic Acid
OH
Carboxyl
Estradiol
(estrogen)
HO
Hydroxyl
Female lion
OH
Carbonyl
(middle)
O
Male lion
Wohler
1828
Testosterone
Amino
Urea
Structure
Compound
Name
Alcohols
Properties
Polar, attracts
water (good
solvent)
Structure
Compound
Name
Aldehydes
Properties
Structural
isomers with
different
properties
Structure
Compound
Name
Ketones
Properties
Structural
isomers with
different
properties
Structure
Compound Carboxylic acid
Name
(organic acids)
Properties
Acidic
properties
Structure
Compound
Name
Amines
Properties
Basic
properties
Structure
Compound
Name
Phosphates
Properties
Makes the molecule
and anion
Transfer energy
DNA
Structure
Compound
Name
Methylated
compounds
Properties
May affect gene
expression
Structure
Compound
Name
Thiols
Stabilize proteins
Properties
Some can have a
stinky odor – skunk,
rotten eggs, garlic
Methanethiol - It is a colorless gas
with a distinctive putrid smell. It
is a natural substance found in the
blood and brain of humans and
other animals as well as plant
tissues. It occurs naturally in
certain foods, such as some nuts
and cheese. It is also one of the
main compounds responsible for
bad breath and the smell of flatus.


In many carbon compounds, the molecules are built up from
smaller, simpler molecules known as MONOMERS.
Monomers can bind to one another to form complex
molecules known as POLYMERS.
o Large polymers are also called MACROMOLECULES
o The process of reacting monomer molecules together in a chemical
reaction to form polymer chains or three-dimensional networks POLYMERIZATION
 WATER
is the most important inorganic
compound in the body and it participates
in two biological reactions:
o Hydrolysis
o Dehydration Synthesis
 Breaking
down polymers by adding a water
molecule.
 Breaking
down polymers by adding a water
molecule.
C12H22O11 + H2O  C6H12O6 + C6H12O6
 Build
up large molecules by releasing a
molecule of water.
 Build
up large molecules by releasing a
molecule of water.
C6H12O6 + C6H12O6  C12H22O11 + H2O
 The
four main classes of organic compounds
essential to all living things are made from
CARBON, HYDROGEN, and OXYGEN atoms, but
in different ratios giving them different
properties.
Made of carbon, hydrogen, and oxygen with H to O
in a 2:1 ratio
 Monosaccharides are a single sugar - MONOMER
 Source of energy
 Can be in straight or ring form
 -ose ending for sugars

Glucose (C6H12O6)
Ribose (C5H10O5)

Glucose, galactose, and fructose all have the same molecular
formula but differ in the arrangement of atoms = ISOMERS
o Molecular formula = C6H12O6 (hexoses)
C5H10O5 (pentoses)
Type of
Sugar
Name of
Sugar
Description of Sugar
Pentose
ribose
Found in RNA
Pentose
deoxyribose
Found in DNA
Hexose
glucose
Hexose
fructose
Hexose
galactose
In blood; cell’s main
energy source
In fruit; sweetest of
monomers
In milk
 Disaccharides
are double sugars
 Two monosaccharides condense to form disaccharides
o Formed by dehydration synthesis
o Molecular formula = C12H22O11
 Bond
that joins monosaccharides (carbohydrates) =
glycosidic bond
A disaccharide is produced by joining
2 monosaccharide (single sugar) units.
In this animation, 2 glucose molecules are combined using
a condensation reaction, with the removal of water.
Glucose molecules joining to form a disaccharide
Condensation of Monosaccharides
Name of
Disaccharide
2 single sugars that
join to form the
disaccharide
Sucrose
Glucose + Fructose
Table Sugar
Lactose
Glucose + Galactose
In milk
Maltose
Glucose + Glucose
In malt
Description of Sugar




Polysaccharides many sugars:
General formula – (C6H10O5)n plus H2O (n = # monomers)
Formed by dehydration synthesis
Long chains of glucose molecules
Name of
Polysaccharide
Description of Sugar
• Animal polysaccharide - stores excess sugar
• Stored in liver and muscles
Glycogen
• Muscle contraction & movement
(animal starch)
• Broken down into glucose and released into
blood for quick energy
• Plant polysaccharide
Starch
• Stores excess sugar
• Gives plants strength and rigidity
• Major component of wood and paper
Cellulose
• Component of cell wall




Elements – carbon, hydrogen, and oxygen (NOT a 2:1 H:O ratio)
Do not dissolve in water
Lipids contain a large number of C-H bonds which store more
energy than C-O bonds in carbohydrates
Monomers: glycerol and fatty acid

Fatty Acids:
o Fatty acids are unbranched C-chains  (12-28 C) with a
carboxyl group (acid) at one end
• The carboxyl end is POLAR and attracted to water – HYDROPHILIC
• The hydrocarbon end is NONPOLAR and does not interact with water –
HYDROPHOBIC
General
Structure
Saturated (single bonds)
Unsaturated (double bonds)

Three major roles of lipids in living organisms:
o Lipids can be used to store energy
o Lipids are important parts of biological membranes
o Lipids are waterproof coverings
Saturated
Fatty Acids
• Carbon atoms with 4 atoms
covalently bonded
• All single bonds
• High melting points
• Solid @ room temperature
• Ex.) animal fat, shortening
Unsaturated
Fatty Acids
• Carbon not bonded to the
maximum # of atoms
• There are double bond(s)
• polyunsaturated
• Liquid @ room temperature
• Primarily in plants
• Energy storage in animals

Lipids (fats, oils, and waxes) are formed by a glycerol molecule
bonding to fatty acid(s)
o formed by dehydration synthesis
 Three
fatty acids attached to glycerol


Two fatty acids joined to a glycerol
Makes up cell membrane - PHOSPHOLIPID BILAYER



Elements: Carbon, Hydrogen, Oxygen, Nitrogen
Monomer: AMINO ACID (20 different kinds)
Each amino acid has a central carbon atom bonded to 4
other atoms or functional groups

Bond that joins amino acids (protein) = PEPTIDE BOND
Formation of a peptide bond
amino acid 1
amino acid 2
Peptide
bond
dipeptide
water
1.
2.
3.
4.
5.
Control the rate of reactions
Regulate cell processes
Form important cellular structures
Transport substances into or out of cells
Help to fight disease
Enzyme + Substrate = ES complex  EP complex = Enzyme + product(s)
 Protein
that has lost its active conformation, or shape
 Denaturing caused by:
o Temperature
o Solute (salt) Concentration
o pH
Large, complex organic compounds that store
information in cells, using a system of four compounds
to store hereditary information, arranged in a certain
order as a code for genetic instructions of the cell.
 Elements: Carbon, Hydrogen,
Oxygen, Nitrogen, Phosphorus
 Monomer: Nucleotide
1. Phosphate group

(Phosphoric Acid)
5-carbon (pentose) sugar
(Deoxyribose or Ribose)
3. Nitrogenous Base
2.
There are FOUR
Nitrogen bases
Nucleotides combine, in DNA to form a double helix, and
in RNA a single helix
 The sides of the ladder are made
up of the phosphate group and
the sugar and the rungs of the
ladder are nitrogen bases
 Examples of Nucleic Acids:
1. Deoxyribonucleic Acid (DNA)
2. Ribonucleic Acid (RNA)

Nucleic Acids and Dehydration Synthesis