Carbon Chemistry: The Molecular Diversity of Life and
The Structure and Function of Large Biological Molecules
Essential
Elements of Life
• Of the 92 naturally
occurring elements,
only ~20% are essential
for life
• Different organisms
require different types
of elements
• 96% of human body is
made up of O, N, C, H
• The others are known
as Trace elements
Organic
Chemistry (<3)
Organic = Carbon (C)
Organic chemicals were
thought to be those that
arise from living organisms
Urey and Miller (1953)
showed that organic
compounds can be made
from abiotic sources
Urey and Miller Experiment –
Life from Non-life
Miller’s experiment supported the
idea that organic compounds,
thought only to be contained in
living organisms, could be
synthesized in the primitive
conditions of early Earth.
Carbon: The element of life
• 4 valence electrons
• Each atom can
generate 4 covalent
bonds
• Can bond with other C
or other elements –
diversity!
Hydrocarbons
Consist only of C and H
Not prevalent in living
organisms
But many organic
molecules have
hydrocarbon regions
Contain large amounts of
energy in these bonds
Hydrocarbon Diversity
Saturated vs. Unsaturated
• Double bonds
change the
structure!
• Effects the
chemistry of the
compound!
• Changes melting
and boiling points
Isomers
• Compounds with the same number of atoms
of the same elements but different structures.
• Differences in structure lead to different
properties.
• 3 types: Structural, cis-trans, enatiomers
Structural
Isomers
Arrangement of atoms vary,
but same molecular formula
The number of possible
isomers increases with
number of C in skeleton
Cis and Trans Isomers
• Double covalent bond
between 2 C creates
inflexibility.
• The remaining 2 bonds
have different spatial
arrangements due to
inflexibility.
• Cis = same side
• Trans = opposite sides
Enantiomers:
L and D
Enantiomers are mirror
images of each other due to
an asymmetric C (because of
4 different bonds)
Enantiomers become
important when discussing
biochemistry – only 1 form is
typically “active”