Question

Our vision can adapt to change between bright light and dark, but it takes a moment because the _____ in our receptor cells must break apart into _____ and _____ for light adaptation and recombine for dark adaptation.

Answer 1

Our vision can adapt to change between bright light and dark, but it takes a moment because the rhodopsin in our receptor cells must break apart into all-trans-retinal and scotopsin for light adaptation and recombine for dark adaptation.  

Rhodopsin is a pigment-containing sensory protein (photopigment) that converts light into an electrical signal. Rhodopsin consists of 11-cis retinal combined with scotopsin. When rhodopsin absorbs light, retinal changes from 11-cis to all-trans retinal and the retinal-scotopsin complex breaks down. This process is called bleaching of the pigment and it triggers a signal transduction along the optic nerve to the visual cortex in the brain.
In the dark, rhodopsin regenerates.