Initiation of visual impulse is associated with:
When light falls on rhodopsin, it is absorbed by rhodopsin causing isomerization of the retinaldehyde from 11-cis to all-trans form, and a conformational change in opsin. This results in the release of retinaldehyde from the protein, and the initiation of a nerve impulse. The final step is hydrolysis to release all-trans-retinaldehyde and opsin. Ref: Harper's Illustrated Biochemistry, 28th Edition, Page 44
Condensation of opsin with vitamin A aldehyde
Photoisomerization and hydrolysis of visual purple
INADP
I NAD