Carbon can form diverse and complex molecules and is the main component of biological molecules besides water. It can bond up to four other atoms in chains, branches and rings to form the carbon skeletons of organic compounds. The number and arrangement of functional groups like hydroxyl, carbonyl, carboxyl, amino and phosphate groups attached to these carbon skeletons determine each molecule's unique properties and ability to undergo chemical reactions. Isomers are compounds with the same molecular formula but different structures or spatial arrangements that can have different properties.

1. Chapter 4 Carbon and the Molecular Diversity of Life

5. LE 4-3 Molecular Formula Structural Formula Ball-and-Stick Model Space-Filling Model Methane Ethane Ethene (ethylene)

7. LE 4-5 Length Ethane Propane Butane 2-methylpropane (commonly called isobutane) Branching Double bonds Rings 1-Butene 2-Butene Cyclohexane Benzene

14. LE 4-9 Estradiol Testosterone Male lion Female lion

16. LE 4-10aa STRUCTURE (may be written HO—) NAME OF COMPOUNDS Alcohols (their specific names usually end in -ol ) Ethanol, the alcohol present in alcoholic beverages FUNCTIONAL PROPERTIES Is polar as a result of the electronegative oxygen atom drawing electrons toward itself. Attracts water molecules, helping dissolve organic compounds such as sugars (see Figure 5.3).

17. LE 4-10ab STRUCTURE NAME OF COMPOUNDS Ketones if the carbonyl group is within a carbon skeleton EXAMPLE Acetone, the simplest ketone A ketone and an aldehyde may be structural isomers with different properties, as is the case for acetone and propanal. Aldehydes if the carbonyl group is at the end of the carbon skeleton Acetone, the simplest ketone Propanal, an aldehyde FUNCTIONAL PROPERTIES

18. LE 4-10ac STRUCTURE NAME OF COMPOUNDS Carboxylic acids, or organic acids EXAMPLE Has acidic properties because it is a source of hydrogen ions. Acetic acid, which gives vinegar its sour taste FUNCTIONAL PROPERTIES The covalent bond between oxygen and hydrogen is so polar that hydrogen ions (H + ) tend to dissociate reversibly; for example, Acetic acid Acetate ion In cells, found in the ionic form, which is called a carboxylate group.

19. LE 4-10ba STRUCTURE NAME OF COMPOUNDS Amine EXAMPLE Because it also has a carboxyl group, glycine is both an amine and a carboxylic acid; compounds with both groups are called amino acids. FUNCTIONAL PROPERTIES Acts as a base; can pick up a proton from the surrounding solution: (nonionized) Ionized, with a charge of 1+, under cellular conditions Glycine (ionized)

20. LE 4-10bb STRUCTURE (may be written HS—) NAME OF COMPOUNDS Thiols EXAMPLE Ethanethiol FUNCTIONAL PROPERTIES Two sulfhydryl groups can interact to help stabilize protein structure (see Figure 5.20).

21. LE 4-10bc STRUCTURE NAME OF COMPOUNDS Organic phosphates EXAMPLE Glycerol phosphate FUNCTIONAL PROPERTIES Makes the molecule of which it is a part an anion (negatively charged ion). Can transfer energy between organic molecules.