Research - Decoding Odors

The world is made of atoms. Those atoms connect to make molecules and molecules are what we smell. Though we know almost everything possible about molecules, we don't have an exact answer on how is smell written into molecules? And how do our noses interact with scent molecules? Til now, there are a few proposed theory on how the nose works.

The prevailing theory:
First refined in 1952 by John Amoore at Oxford University, proposes that the shape of a molecule determines its smell. eg, a rose molecule smells like a rose molecule because its shape is coded precisely for the nose to interpret this way. How it works is that the shape of an airborne molecule (the key) fits into complementary odorant receptor proteins on the outside of the nasal cell (the lock).

Vibrational theory
In 1996, Luca Turin, a biophysicist at University College London, states that molecules in every substance generate a specific vibration frequency that the nose interprets as a distinct smell. The vibration frequency of odor molecules is converted to smell recognition via a form of electron tunnelling with the help of receptors in the lining of the nose. The vibrational theory suggested that the way we smell is similar to the way we hear, but instead of music get the chemical melody of scent.


This diagram shows the receptor neurons in the nose that convert odors to electrical signals that the brain can interpret.



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