stereochemical smell theory
the concept that certain odors are perceived because they are produced by odorants whose stereochemical properties have certain shapes. Seven classes of odorants are postulated: camphoraceous, ethereal, floral, minty, musty, pungent, and putrid. The odorant molecules are thought to fit receptors in a lock-and-key manner that causes the neural membrane to become depolarized or hyperpolarized, which in turn is the cue that produces an odor experience. Since many odorants that share a similar molecular structure produce different odor experiences, it has been hypothesized that the lock-and-key principle may be modified by the orientation of the molecules at the receptor surfaces. Also called lock-and-key theory; steric theory of odor.