Question

Compare and contrast the sensory transduction mechanisms of vision, olfaction and taste in 5 different ways. Please make a distinction for invertebrate and vertebrate mechanismsif they differ.

Answer 1

Vision
Energy - Photons
Receptor - GPCR family rhodopsin
G protein - Transducin
G protein target - Phosphodiesterase
Secondary messanger - cGMP

Olfaction

Energy - Molecules
Receptor - family olfactory
G protein - Golf
G protein target - Adenyl cyclase, phospholipase C
Secondary messanger - cAMP, IP3

Taste

Energy - Sugar, proteins etc
Receptor - GPCR family Gustatory
G protein - Ggust
G protein target - Adenyl cyclase, phospholipase C
Secondary messanger - cAMP, IP3

In vertebrates the senses of taste and smell are clearly defined by two separate sensory organs, namely, the tongue and the nose.

In invertebrate animals, the distinction is less clear, as the sense of taste is generally not confined to one specific organ. Invertebrate taste receptors can be located on the same organ as olfactory receptors, or they can be distributed on different appendages all over the body, including parts of the mouth, feet, antennae, and ovipositor.