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

2. Concept 4.1
Compounds containing carbon are said to be organic compounds.
Carbon atoms are very versatile.
- have 4 valence electrons. It will share electrons in 4 covalent bonds (tetravalence)

3. Concept 4.2
Variation in carbon skeletons contribute to the diversity of organic molecules.
- long chains form carbon skeletons
- often bonded to several hydrogen atoms forming a hydrocarbon.

4. Concept 4.2

5. Concept 4.2
Isomers: compounds that have the same molecular formula, but different structures (with different properties).
- structural: differ in the covalent arrangements of atoms.
- geometric: same covalent properties, but differ in spatial arrangements.
- enantiomers: mirror images

6. Concept 4.2

7. Concept 4.3
Functional groups: components of molecules that are often involved in chemical reactions.
- ex. difference between testosterone and estrogen.

8. Concept 4.3
Estradiol
Testosterone

9. Concept 4.3 6 functional groups are commonly found.
- hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, and phosphate.
- all are hydrophilic and increase the solubility of organic compounds in water.

10. Concept 4.3 Hydroxyl group (-OH) names usually end with suffix –ol
ex. ethanol
organic compounds w/ OH are alcohols
note: do not confuse w/ OH-

11. Concept 4.3 Carbonyl group (-C=O)
-carbon double bonded to an oxygen atom.
- if at the end of the carbon skeleton will be an aldehyde (ex. propanol)
- if in the middle of a carbon skeleton will be a ketone (ex. acetone)

12. Concept 4.3 Carboxyl group (-COOH)
- oxygen is double bonded to a carbon that is also bonded to a hydroxyl group
- compounds are called carboxylic acids (ex. acetic acid)
- has acidic properties w/ the loss of H+ ions

13. Concept 4.3 Carboxyl STRUCTURE NAME OF COMPOUND
Carboxylic acids, or organic acids
Has acidic properties
because the covalent bond between oxygen and hydrogen is so polar; for example,
EXAMPLE
FUNCTIONAL
PROPERTIES
Acetic acid, which gives vinegar its sour taste
Acetic acid
Acetate ion
Found in cells in the ionized form with a charge of 1– and called a carboxylate ion (here, specifically, the acetate ion).

14. Concept 4.3 Amino group (-NH2)
- a nitrogen atom is bonded to two hydrogen atoms and a carbon skeleton
- compounds are called amines
- compounds that have both amino and carboxyl groups are called amino acids
- ex. Glycine
- amino group can act as a base (NH3+)

15. Concept 4.3 Amino STRUCTURE NAME OF COMPOUND Amines EXAMPLE
Acts as a base; can pick up an H+ from the surrounding solution (water, in living organisms).
FUNCTIONAL
PROPERTIES
Glycine
Because it also has a carboxyl group, glycine is both an amine and
a carboxylic acid; compounds with both groups are called amino acids.
(nonionized)
(ionized)
Ionized, with a charge of 1+, under cellular conditions.

16. Concept 4.3 Sulfhydryl group (-SH)
- Sulfur is bonded to a hydrogen and a carbon skeleton
- compounds with –SH are called thiols
- help stabilize the structure of proteins

17. Concept 4.3 Phosphate group (-OPO32-)
- formed by dissociation of phosphoric acid (H3PO4)
- used in the transfer of energy between organic molecules.

18. Concept 4.3 Phosphate NAME OF COMPOUND STRUCTURE Organic phosphates
EXAMPLE
Contributes negative charge to the molecule of which it is a part (2– when at the end of a molecule; 1– when located internally in a chain of phosphates).
FUNCTIONAL
PROPERTIES
Glycerol phosphate
In addition to taking part in many important chemical reactions in cells, glycerol phosphate provides the backbone for phospholipids, the most prevalent molecules in cell membranes.
Has the potential to react with water, releasing energy.