QS Study

Rhodopsin is the primary photoreceptor molecule of vision. The visual purple or light-sensitive chemical in the rods is called prolepsis. Rhodopsin is a chromoprotein containing a carotene pigment (Chromophore group) as a prosthetic group this group is the specific part of the molecule and is a derivative of vitamin ‘A’; it is present in the outer segment of the rods only. It is bleached on exposure to light into retina and opsin. It is a light-sensitive receptor protein involved in visual phototransduction. In humans, it is regenerated fully in about 30 minutes; after which rods are more sensitive.

Fig: Rhodopsin

Rhodopsin is found in specialized light receptor cells called rods. It is a red photosensitive tincture in the retinal rods of the eye of most vertebrates that is vital in vision in dim light. As part of the light-sensitive tissue at the back of the eye (the retina), rods provide vision in low light. Other light receptor cells in the retina, called cones, are responsible for vision in bright light.