1. Carbon and the Molecular Diversity of Life4
Carbon and the Molecular Diversity of Life
Lecture Presentation by Nicole Tunbridge and
Kathleen Fitzpatrick

2. Carbon: The Backbone of Life
Living organisms consist mostly of carbon-based compounds
Carbon is unparalleled in its ability to form large, complex, and varied molecules
Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are all composed of carbon compounds

3. Carbon can bond to four other atoms or
Figure 4.1a
Figure 4.1a What properties make carbon the basis of all life? (part 1: carbon atom)
Carbon can bond to four other atoms or
groups of atoms, making a large variety of
molecules possible.

4. Concept 4.1: Organic chemistry is the study of carbon compounds
Organic chemistry is the study of compounds that contain carbon
With four valence electrons, carbon can form four covalent bonds with a variety of atoms
This ability makes large, complex molecules possible

5. Molecular Formula Structural Formula Space-Filling Model Molecule
Figure 4.3
Molecular
Formula
Structural
Formula
Space-Filling
Model
Molecule
Ball-and-Stick Model
(a) Methane
CH4
(b) Ethane
C2H6
Figure 4.3 The shapes of three simple organic molecules
(c) Ethene
(ethylene)
C2H4

6. Carbon atoms can partner with atoms other than hydrogen; for example:
Carbon dioxide: CO2
Urea: CO(NH2)2

7. Figure 4.UN02
Urea
Figure 4.UN02 In-text figure, urea, p. 60

8. Molecular Diversity Arising from Variation in Carbon Skeletons
Carbon chains form the skeletons of most organic molecules
Carbon chains vary in length and shape

9. 2-Methylpropane (isobutane)
Figure 4.5
(a) Length
(c) Double bond position
Ethane
Propane
1-Butene
2-Butene
(b) Branching
(d) Presence of rings
Figure 4.5 Four ways that carbon skeletons can vary
Butane
2-Methylpropane
(isobutane)
Cyclohexane
Benzene

10. Hydrocarbons
Hydrocarbons are organic molecules consisting of only carbon and hydrogen
Many organic molecules, such as fats, have hydrocarbon components
Hydrocarbons can undergo reactions that release a large amount of energy

11. Isomers
Isomers are compounds with the same molecular formula but different structures and properties
Structural isomers have different covalent arrangements of their atoms
Cis-trans isomers have the same covalent bonds but differ in spatial arrangements
Enantiomers are isomers that are mirror images of each other

12. (a) Structural isomers
Figure 4.7
(a) Structural isomers
Pentane
2-methyl butane
(b) Cis-trans isomers
cis isomer: The two Xs are
on the same side.
trans isomer: The two Xs are
on opposite sides.
(c) Enantiomers
Figure 4.7 Three types of isomers, compounds with the same molecular formula but different structures
CO2H
CO2H C C H
NH2
NH2 H
CH3
CH3
L isomer
D isomer

13. Enantiomers are important in the pharmaceutical industry
Two enantiomers of a drug may have different effects
Usually only one isomer is biologically active
Differing effects of enantiomers demonstrate that organisms are sensitive to even subtle variations in molecules

14. Effective Enantiomer Ineffective Enantiomer Drug Effects Reduces
Figure 4.8
Effective
Enantiomer
Ineffective
Enantiomer
Drug
Effects
Reduces
inflammation
and pain
Ibuprofen
S-Ibuprofen
R-Ibuprofen
Relaxes bronchial
(airway) muscles,
improving airflow
in asthma
patients
Figure 4.8 The pharmacological importance of enantiomers
Albuterol
R-AIbuterol
S-AIbuterol

15. Functional groups are the components of organic molecules that are most commonly involved in chemical reactions
The number and arrangement of functional groups give each molecule its unique properties

16. The seven functional groups that are most important in the chemistry of life
Hydroxyl group
Carbonyl group
Carboxyl group
Amino group
Sulfhydryl group
Phosphate group
Methyl group

17. Figure 4.9 Some biologically important chemical groups
Compound Name
Examples
Hydroxyl group (—OH)
Alcohol
Ethanol
Carbonyl group
( C＝O) —
Ketone
Aldehyde
Acetone
Propanal
Carboxyl group (—COOH)
Carboxylic acid, or
organic acid
Acetic acid
Amino group (—NH2)
Amine
Glycine
Sulfhydryl group (—SH)
Thiol
Cysteine
Figure 4.9 Some biologically important chemical groups
Phosphate group (—OPO32−)
Organic
phosphate
Glycerol phosphate
Methyl group (—CH3)
Methylated
compound
5-Methyl cytosine

18. ATP: An Important Source of Energy for Cellular Processes
An important organic phosphate is adenosine triphosphate (ATP)
ATP consists of an organic molecule called adenosine attached to a string of three phosphate groups
ATP stores the potential to react with water, a reaction that releases energy to be used by the cell

19. Figure 4.UN04
Adenosine
Figure 4.UN04 In-text figure, ATP phosphate chain, p. 64

20. Reacts with H2O P P P Adenosine P P P Adenosine Energy ATP Inorganic
Figure 4.UN05
Reacts
with H2O P P P
Adenosine P P P
Adenosine
Energy i
ATP
Inorganic
phosphate
ADP
Figure 4.UN05 In-text figure, ATP to ADP reaction, p. 64