Opsin molecule 插畫檔

Opsin. Molecular model of a ligand-free opsin molecule. Opsins are found in photoreceptor cells (rods and cones) in the retina of the eye. This opsin molecule forms a complex with retinal, called rhodopsin or visual purple, in rod cells. The retinal molecule absorbs light, which causes it to change shape and separate from the opsin. This initiates the transmission of nerve impulses to the brain, leading to the sensation of vision. The great sensitivity of rhodopsin is what allows vision in dim light.