CHAPTER 4
CARBON AND THE MOLECULAR
DIVERSITY OF LIFE
Section A: The Importance of Carbon
1. Organic chemistry is the study of carbon compounds
2. Carbon atoms can form diverse molecules by bonding to four other atoms
3. Functional groups are the parts of molecules involved in chemical reactions
Introduction
• Although cells are _________ water, the rest
consists mostly of carbon-based compounds.
• Four major groups of macromolecules are
1. _____________
2. ______________
3. _______________
4. _______________
all composed of carbon atoms bonded to each other
and elements.
• hydrogen (H), oxygen (O), nitrogen (N), sulfur
(S), and phosphorus (P).
1. ____________________ is the study of
carbon compounds
• Organic compounds range from simple (CO2 or
CH4) to complex molecules (proteins of 100,000
daltons).
• The overall percentages of the major elements of life ___
________________ are quite ___________ from one
organism to another.
2. Carbon atoms are the ________________
building blocks of molecules
• Total of __electrons (__ in the first shell and __in the
second shell).
• Carbon usually completes its ___________ shell by
_________ electrons with other atoms in four covalent
bonds.
• This ______________ by carbon makes large, complex
molecules possible.
•The ___________ of carbon and its partners can be
viewed as the ____________ that governs the
_____________ of organic molecules.
• In _________________, one carbon atom forms two
________________ with two different oxygen
atoms.
• The structural formula, _____________, shows that each
atom has completed its valence shells.
• CO2 is the source for all _________________ in
organisms via the process of_________________.
• ______, CO(NH2) 2, is another
simple organic molecule in
which each atom has enough
covalent bonds to complete
H
its __________ shell.
O
C
N
H
3. Variation in carbon skeletons contributes to the
diversity of organic molecules
• Carbon chains form the ______________ of most
organic molecules.
• The skeletons may vary in length and may be ________,
___________, or arranged in closed ________.
Length
Branched
Double bonds
Rings
Fig. 4.5
• ________________ are organic molecules that
consist of only _________ and ___________ atoms.
• Hydrocarbons are the major component of____________.
• Petroleum is a _____________ because it consists of the
partially decomposed remains of _______________ .
• _____ are biological
molecules that have
long hydrocarbon
tails attached to a
__________________
component.
Fig. 4.6
• ________ are compounds that have the same
________________ but different ____________ and
therefore different chemical properties.
• Example: butane and isobutane have the same molecular
formula C4H10, but butane has a _________ skeleton and
isobutane has a ______________ skeleton.
butane
Fig. 4.7a
isobutane
• ___________________ are molecules that are
mirror images of each other
• __________________ are possible if there are ______
different atoms or groups of atoms bonded to a carbon.
• If true, it is possible to arrange the four groups in space
in two different ways that are _____________________.
• Usually one is
biologically active,
the other inactive.
Fig. 4.7c
• Even the subtle structural differences in two
_____________________ have important
functional significance because of
_______________properties from the specific
arrangements of atoms.
EXAMPLE :One enantiomer of the drug ____________
reduces morning sickness…..
• ….but the other isomer causes severe
________________
ANOTHER EXAMPLE:
• The L-Dopa isomer
is an effective treatment
of _____________ disease,
but the D-Dopa isomer
is ______________.
Fig. 4.8
4. Functional groups contribute to the
molecular diversity of life
• The components of organic molecules that are most
commonly involved in __________________ are
known as _________________.
• Functional groups are __________________ that replace
one or more _________________ in the carbon skeleton of
the hydrocarbon.
• Each functional groups behaves ________________
from one organic molecule to another.
• The _____________ and _______________ of
functional groups help give each molecule its unique
properties.
• The basic structure of _______________ (male
hormone) and _______________ (female hormone)
is identical.
• Both are steroids with four fused carbon rings, but
they differ in the functional groups attached to the
rings.
• These then interact with different _________ in the
body.
Fig. 4.9
• There are _______________________ that are
most important to the chemistry of life:
• 1) ____________
• 2) ____________
• 3) _____________
• 4) _____________
• 5) _____________
• 6) _____________
• All are ____________ and ____________
solubility of organic compounds in water.
• 1) ____________________Polar covalent bonds hydroxyl groups improve the
solubility
Organic compounds with hydroxyl groups are _______
and their names typically end in -ol.
See pages 64-65
• 2)____________________• ______________- If the carbonyl group is on the end of
the skeleton
• If not, then the compound is a ____________.
See pages 64-65
• 3) _______________________• Compounds with carboxyl groups are _____________.
• A carboxyl group acts as an acid
See pages 64-65
• 4) _______________________ • Organic compounds with amino groups are _______
• The amino group acts as a base
• Amino acids, the building blocks of proteins, have _____
and ___________ groups.
See pages 64-65
• 5) ______________________ .
• resembles a hydroxyl group in shape.
• stabilize the structure of proteins
• Organic molecules with sulfhydryl groups are ______.
See pages 64-65
• 6) ____________________________ • connects to the carbon backbone via one of its oxygen
atoms.
• are anions with two negative charges as two protons have
dissociated from the oxygen atoms.
See pages 64-65
2. The chemical elements of life: a review
• Living matter consists mainly of ______________
with smaller amounts of sulfur and phosphorus.
• These elements are linked by strong ____________
bonds.
• Carbon with its ______ covalent bonds is the basic
building block in molecular architecture.
• The great diversity of organic molecules with their
special properties emerge from the unique
arrangement of the carbon skeleton and the functional
groups attached to the skeleton.