photopigment
/ˈfəʊtəʊˈpɪɡm(ə)nt
/noun
A pigment whose chemical state depends on its degree of illumination, such as those in the retina of the eye.The difference absorption spectroscopy in both living plasmodium and cell homogenate shows that there is a photopigment which converts reversibly between red and far-red types....
- There is no physiological evidence for a third photopigment sensitive to blue wavelengths.
- It could involve retinal photoreceptors, extraretinal photoreceptors in the pineal or elsewhere, photopigments such as cryptochromes within the retina or brain, or it might be mediated through a non-visual pathway.