odor receptor

An olfactory receptor is a protein that binds to odor molecules, playing a crucial role in the sense of smell. These receptors are found in many animals, including humans, where they are located on olfactory receptor cells clustered in the nasal cavity's olfactory epithelium.1

Each receptor cell has cilia that extend to the nasal cavity's surface, where they detect odor molecules. The receptor proteins are embedded in the cell membrane, with ends projecting both inside and outside the cell. This structure allows external chemicals to trigger changes within the cell without entering it.1

The specific sequence of amino acids in these proteins determines their shape and which odor molecules they can bind to, similar to a lock and key mechanism. When a molecule binds, it causes a conformational change in the protein, initiating a cascade of events within the cell that ultimately leads to an electrical signal sent to the brain. This process enables animals to distinguish between a vast array of smells.12