Do Odorant Molecules Enter the Cell?

This makes it possible for a chemical outside the cell, such as a molecule of an odorant, to communicate with and produce changes in the cellular machinery without entering the cell. The outer and inner ends of receptor proteins involved in smell are connected by a chain of amino acids.

What do odorant molecules bind to?

Odorant molecules bind to odorant receptors (R) located in the ciliary membrane, thus activating a G protein (Golf) that stimulates adenylyl cyclase (AC), producing an increase in the generation of cAMP from ATP.

What happens when an odorant binds to receptor proteins?

Binding of the odorant activates a G protein coupled to the receptor on its cytoplasmic side. This activates adenylyl cyclase, an enzyme embedded in the plasma membrane of the cilia. Adenylyl cyclase catalyzes the conversion of ATP to the "second messenger" cyclic AMP (cAMP) in the cytosol.