More about the Biological Importance of Chirality

Chiral molecules can show their handedness in many ways, including the way they affect human beings. One enantiomeric form of a compound called limonene (Section 23.3) is primarily responsible for the odor of oranges and the other enantiomer for the odor of lemons. 

One enantiomer of a compound called carvone (Review Problem 5.14) is the essence of caraway, and the other is the essence of spearmint. 

The activity of drugs containing chirality centers can similarly vary between enantiomers, sometimes with serious or even tragic consequences. For several years before 1963 the drug thalidomide was used to alleviate the symptoms of morning sickness in pregnant women. In 1963 it was discovered that thalidomide was the cause of horrible birth defects in many children bom subsequent to the use of the drug. 

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