How do odor molecules interact with olfactory receptors in the nose?

The sense of smell, or olfaction, is a complex process involving the detection of odor molecules by olfactory receptors in the nose. When odor molecules enter the nose, they dissolve in the mucus lining the nasal cavity and bind to olfactory receptor proteins located on the cilia of olfactory receptor neurons. This binding triggers a series of biochemical reactions that generate an electrical signal, which is then transmitted to the brain for processing.

Each olfactory receptor neuron in the nose expresses only one type of olfactory receptor protein, and each receptor protein is specific to certain odor molecules. The human nose can detect thousands of different odor molecules, and this is due to the large number of different olfactory receptor proteins that are expressed in the nose.

The interaction between odor molecules and olfactory receptors is not completely understood, but it is thought to involve a combination of shape, size, and chemical properties of both the odor molecule and the receptor protein. When an odor molecule binds to its corresponding receptor protein, it changes the shape of the protein, which triggers a series of biochemical events that ultimately result in the generation of an electrical signal.