The use of sensory G protein-coupled receptors that recognize chemical sensants, parti-cularly those involving olfactory and taste receptors; polypeptide fragments and mutants thereof; classes of such receptors; polynucleotides encoding such receptors, fragments and mutants thereof, and representatives of receptor classes; genetic vectors including such polynucleotides; and cells and non-human organisms engineered to express such receptor complexes, fragments and mutants of an olfactory or taste receptor, and representatives of receptor classes to simulate sensory perception of odorants and tastants is described. The use of such products as a biosensor or a component thereof to detect, identify, measure, or otherwise process the event of binding between the receptor and its cognate ligand (i.e., chemical sensant) is also described. The invention has application, for example, in the design and formulation of odorant and tastant compositions.