Chapter 4

Organic chemistry is currently defined as (A) the study of compounds made only by living (B) cells. (B) the study of carbon compounds. (C) the study of natural (as opposed to synthetic) (D) the study of hydrocarbons.

MAKE CONNECTIONS Which chemical group is most likely to be responsible for an organic molecule behaving as a base (see Concept 3.3\() ?\) \(\begin{array}{ll}{\text { (A) hydroxyl }} & {\text { (C) amino }} \\ {\text { (B) carbonyl }} & {\text { (D) phosphate }}\end{array}\)

VISUAL SKILLS Visualize the structural formula of each of the following hydrocarbons. Which hydrocarbon has a double bond in its carbon skeleton? $$\begin{array}{ll}{\text { (A) } \mathrm{C}_{3} \mathrm{H}_{8}} & {\text { (C) } \mathrm{C}_{2} \mathrm{H}_{4}} \\ {\text { (B) } \mathrm{C}_{2} \mathrm{H}_{6}} & {\text { (D) } \mathrm{C}_{2} \mathrm{H}_{2}}\end{array}$$

SCIENTIFIC INQUIRY 50 years ago, pregnant women who were prescribed thalidomide for morning sickness gave birth to children with birth defects. Thalidomide is a mixture of two enantiomers; one reduces morning sickness, but the other causes severe birth defects. Today, the FDA has approved this drug for non-pregnant individuals with Hansen's disease (leprosy) or newly diagnosed multiple myeloma, a blood and bone marrow cancer. The beneficial enantiomer can be synthesized and given to patients, but over time, both the beneficial and the harmful enantiomer can be detected in the body. Propose a possible explanation for the presence of the harmful enantiomer.

WRITE ABOUT A THEME: ORGANIZATION In \(1918,\) an epidemic of sleeping sickness caused an unusual rigid paralysis in some survivors, similar to symptoms of advanced Parkinson's disease. Years later, L-dopa (below, left), a chemical used to treat Parkinson's disease, was given to some of these patients. L-dopa was remarkably effective at eliminating the paralysis at least temporarily. However, its enantiomer, D-dopa (right) was subsequently shown to have no effect at all, as is the case for Parkinson's disease. In a short essay \((100-150\) words), discuss how the effectiveness of one enantiomer and not the other illustrates the theme of structure and function.