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

2. Overview: Carbon: The Backbone of Life
Although cells are 70–95% water, the rest consists mostly of carbon-based compounds
Carbon has is unparalleled in its ability to form large, complex, and diverse molecules
Carbon compounds are found in:
Proteins
DNA
Carbohydrates,
Other molecules that distinguish living matter
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3. Concept 4.1: Organic chemistry is the study of carbon compounds
Organic Chemistry is the study of compounds that contain carbon
Organic compounds range from simple molecules to colossal (huge) ones
Most organic compounds contain:
Hydrogen atoms
Carbon atoms
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4. Why can Carbon form large complex and divers molecules?
It has 4 Valence Electrons
It can form 4 Covalent Bonds
Bonds can be
Single
Double
Triple
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5. Why can Carbon form large complex and divers molecules?
It can form large molecules
Molecules can be:
Chains
Ring-Shaped
Branched
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6. The Formation of Bonds with Carbon - Shapes
Carbon has 4 Valence Electrons (tetravalent)
When carbon forms:
4 single bonds  Tetrahedral Shape
A double bond  Flat Shape
Name
Molecular Formula
Structural Formula
Ball-and-Stick
Model
Space-Filling
(a) Methane
(b) Ethane
(c) Ethene
(ethylene)
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7. Most common carbon covalent bonds in living organisms:
Hydrogen
Oxygen
Nitrogen
“Building code” that governs the architecture of living molecules
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8. Example: Carbon dioxide: CO2 O = C = O Urea: CO(NH2)2
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9. Molecular Diversity Arising from Carbon Skeleton Variation
Carbon chains form the skeletons of most organic molecules
Carbon chains vary in length and shape
Ethane
Propane
1-Butene
2-Butene
(c) Double bonds
(d) Rings
Cyclohexane
Benzene
Butane
2-Methylpropane
(commonly called isobutane)
(b) Branching
(a) Length
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10. Many organic molecules, such as fats, have hydrocarbon components
Hydrocarbons
Hydrocarbons are organic molecules consisting of only carbon and hydrogen
Many organic molecules, such as fats, have hydrocarbon components
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11. Structure predicts function: Draw Diagram of hydrocarbon tail in cell membrane & explain how it makes cell membrane selective

12. Hydrocarbons
Hydrocarbons can undergo reactions that release a large amount of energy
Eg. Diesel Fuel - Nonane
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13. Isomers
Isomers are compounds with the same molecular formula but different structures and properties
Structural isomers have different covalent arrangements of their atoms
Example: C5H12
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14. Isomers
Geometric isomers have the same covalent arrangements but differ in spatial arrangements
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15. Isomers Enantiomers are isomers that are mirror images of each other
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16. Enantiomers are important in the pharmaceutical industry:
Two enantiomers of a drug may have different effects
Example: Thalidomide for pregnant women
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17. Effective Enantiomer Ineffective Enantiomer Drug Condition Pain;
inflammation
Ibuprofen
S-Ibuprofen
R-Ibuprofen
Figure 4.8 The pharmacological importance of enantiomers
Albuterol
Asthma
R-Albuterol
S-Albuterol

18. Differing effects of enantiomers demonstrate that organisms are sensitive to even subtle variations in molecules
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19. Distinctive properties of organic molecules depend on:
Concept 4.3: A small number of chemical groups are key to the functioning of biological molecules
Distinctive properties of organic molecules depend on:
The Carbon skeleton
Molecular components attached to it (aka functional groups)
A number of characteristic groups are often attached to skeletons of organic molecules
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20. The Chemical Groups Most Important in the Processes of Life
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
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21. Estradiol Testosterone Fig. 4-9
Figure 4.9 A comparison of chemical groups of female (estradiol) and male (testosterone) sex hormones

22. 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
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23. Group
Structure
Hydroxyl
-OH
Alcohols & helps dissolve molecules such as sugar
Carbonyl
-CO
Ketones & Aldehydes such as sugars
Carboxyl
-COOH
Fatty Acids & Sugars
Amino
-NH2
Amino Acids
Sulfhydryl
-SH
Proteins
Phosphate
PO3
ATP, DNA, Phospholipids
Methyl
CH3
DNA

24. ATP: An Important Source of Energy for Cellular Processes
Adenosine triphosphate (ATP): Is the primary energy-transferring molecule in the cell
Organic molecule called adenosine
Three phosphate groups
Adenosine
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25. Reacts with H2O Energy ATP Inorganic phosphate ADP Adenosine Adenosine
Fig. 4-UN4
Reacts with H2O P P P
Adenosine
P i P P
Adenosine
Energy
ATP
Inorganic phosphate
ADP

26. You should now be able to:
Explain how carbon’s electron configuration explains its ability to form large, complex, diverse organic molecules
Describe how carbon skeletons may vary and explain how this variation contributes to the diversity and complexity of organic molecules
Distinguish among the three types of isomers: structural, geometric, and enantiomer
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27. Name the major functional groups found in organic molecules; describe the basic structure of each functional group and outline the chemical properties of the organic molecules in which they occur
Explain how ATP functions as the primary energy transfer molecule in living cells
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