| In the pure-cone American chameleon retina, all visual opsins including rod opsin are expressed. |
| Every photopigment consists of a derivative of vitamin A linked to a protein molecule called an opsin. |
| Vitamin A then combines with a protein opsin to form rhodopsin. |
| Visual pigments are composed of a light-absorbing chromophore that is bound to the protein opsin. |
| Rhodopsin consists of a protein called opsin bonded to a pigment called retinal. |
| The transport of opsin to the outer segment of photoreceptor cells seems especially critical for viability of these cells. |
