1. Carbon and the Molecular Diversity of Life
Chapter 4
Carbon and the Molecular Diversity of Life

2. Carbon Chemistry
Carbon is the Backbone of Biological Molecules (macromolecules)
All living organisms Are made up of chemicals based mostly on the element carbon
Figure 4.1

3. Carbon Chemistry Organic chemistry is the study of carbon compounds
Carbon atoms can form diverse molecules by bonding to four other atoms
Carbon compounds range from simple molecules to complex ones
Carbon has four valence electrons and may form single, double, or triple bonds
Instead of making quadruple bonds, carbon makes a network solid
Diamond and graphite

4. The bonding versatility of carbon allows it to form many diverse molecules, including carbon skeletons
(a) Methane
(b) Ethane
(c) Ethene (ethylene)
Molecular Formula
Structural Formula
Ball-and-Stick Model
Space-Filling Model H C
CH4
C2H6
C2H4
Name and Comments
Figure 4.3 A-C

5. The electron configuration of carbon gives it covalent compatibility with many different elements
Hydrogen
(valence = 1)
Oxygen
(valence = 2)
Nitrogen
(valence = 3)
Carbon
(valence = 4)
Figure 4.4

6. Carbon may bond to itself forming carbon chains
Carbon chains form the skeletons of most organic molecules
Carbon chains vary in length and shape H C
(a) Length
(b) Branching
(c) Double bonds
(d) Rings
Ethane
Propane
Butane
isobutane
1-Butene
2-Butene
Cyclohexane
Benzene
Figure 4.5 A-D

7. (b) Mammalian adipose cells
Hydrocarbons
Hydrocarbons are molecules consisting of only carbon and hydrogen
Hydrocarbons Are found in many of a cell’s organic molecules
(a) A fat molecule
(b) Mammalian adipose cells
100 µm
Fat droplets (stained red)
Figure 4.6 A, B

8. (a) Structural isomers
Isomers are molecules with the same molecular formula but different structures and properties
Three types of isomers are
Structural
Geometric
Enantiomers H
CO2H
CH3
NH2 C X
(a) Structural isomers
(b) Geometric isomers
(c) Enantiomers
Figure 4.7 A-C

9. Enantiomers Are important in the pharmaceutical industry
L-Dopa
(effective against Parkinson’s disease)
D-Dopa
(biologically inactive)
Figure 4.8