Chapter 4.
The Chemistry of
Carbon
Why study Carbon?
All living things are made of cells
 Cells

◦ ~72% H2O
◦ ~3% salts (Na, Cl, K…)
◦ ~25% carbon compounds
◦
◦
◦
◦
carbohydrates
lipids
proteins
nucleic acids
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Chemistry of Life
Organic chemistry is the study of
carbon compounds
 C atoms are versatile building blocks

◦ bonding properties
◦ 4 stable covalent bonds pair of electrons are shared
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Complex molecules assembled like –
candy
&
toothpicks
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Hydrocarbons

Simplest Carbon molecules =
hydrocarbons
◦ A compound with a combination of Carbon
& Hydrogen

Simplest HC molecule = methane
◦ 1 carbon bound to 4 H atoms
◦ stable
◦ a gas at room temperature
Hydrocarbons can grow

methane
adding C-C bonds
ethane
◦ straight line
 ethane
 hexane
◦ branching
 isohexane
hexane
◦ ring
 cyclohexane
isohexane
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cyclohexane
Diversity of organic molecules
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Isomers

Molecules with same molecular formula
but different structures
◦ different chemical properties – C6H14
Various kinds of isomers

Molecules differ in structural
arrangement of atoms

Around a double bond – alkenes
Isomers of ethene
Most macromolecules are polymers

Three of the four classes of
macromolecules form chainlike molecules
called polymers.
◦ Polymers consist of many similar or identical
building blocks linked by covalent bonds.

The repeated units are small molecules
called monomers. (like links of a chain)
4 MAIN MACROMOLECULES
MOLECULE
Proteins
Lipids
MONOMER
USES
support/motion
(amino acids)
(glycerol & fatty acids)
energy storage/insulation
Carbohydrates
(monosaccharides)
Nucleic acids
(nucleotides)
•
quick energy
store information
They all contain CARBON and are called
ORGANIC molecules
(Also hydrogen, oxygen are in all of them)
Diversity of molecules

Substitute other atoms or groups
around the C
◦ ethane vs. ethanol
 H replaced by an hydroxyl group (–OH)
ethane
ethanol
What element is the blue one
above? How many bonds does it
form?
Hydroxyl

–OH
◦ organic compounds with OH = alcohols
◦ names typically end in -ol
 ethanol
More on
Functional Groups
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Types of functional groups

6 functional groups most important to
chemistry of life:
◦ hydroxyl
◦ carbonyl
◦ carboxyl

amino
sulfhydryl
phosphate
Affect reactivity
◦ hydrophilic
◦ increase solubility in water
◦ Change all kinds of properties
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Carboxyl

–COOH
◦ C double bonded to O & single bonded to OH
group
 compounds with COOH = acids
◦ fatty acids
◦ amino acids
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Amino

-NH2
◦ N attached to 2 H
 compounds with NH2 = amines
◦ amnio acids
 NH2 acts as base
◦ ammonia picks up H+ from solution
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Viva la difference!

Basic structure of male & female
hormones is identical
◦ identical C skeleton
◦ attachment of different functional groups
◦ interact with different targets in the body
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