Question

Photopigments of human eye are composed of a protein called

• A. Melanin
• B. Retinal
• C. Opsin
• D. Myosin
• E. Troponin

Answer 1

Answer: (C)

Opsin

A. Melanin is a pigment responsible for darkness in skin.

B. Retinal is an aldehyde of vitamin A and found bound to photopigments in retina.

C. Opsin are the light sensitive proteins present in photoreceptor cells of retina i.e. cones and rods. Cones contain iodopsin, porpyrosin and cynaopsin and rods contain rhodopsin.

D. Myosin is a motor protein that plays an important role in muscle contraction.

E. Troponin is a protein of muscle fibres.

So, the correct answer is 'Opsin'.