The Gustatory receptors are a divergent group of (non-GPCR) seven-transmembrane chemoreceptors that are expressed in gustatory sensilla receptor neurons. They detect tastants (non-volatile compounds) via contact chemosensation
Olfactory receptor, also called smell receptor, protein capable of binding odour molecules that plays a central role in the sense of smell (olfaction). ... The cilia are covered by the mucus of the nasal cavity, facilitating the detection of and response to odour molecules by olfactory receptors.
Photoreceptors signals color; they only signal the presence of light in the visual field. A given photoreceptor responds to both the wavelength and intensity of a light source. For example, red light at a certain intensity can produce the same exact response in a photoreceptor as the green light of different intensity.
