Question

Photosensitive compound in human eye is made up of
a. Opsin and Retinal
b. Opsin and Retinol
c. Transducin and Retinene
d. Guanosine and Retinol.

Answer 1

Hint: Human eye is a sense organ that reacts to the light and which allows vision. There are cells known as rod and cone cells present in the retina which allow the conscious light perception and vision including color differentiation and give us a perception of depth. The human eye is part of the sensory nervous system.

Complete answer:
There is a photosensitive compound in the human eye which helps in vision of the eye and is called rhodopsin, which is also known as vision purple which has a large protein called opsin and retinal. Retinal is also known as retinaldehyde and is a form of vitamin A. Retinal is bound with the proteins called opsins and they are chemical bases of animal vision. Retinal also plays an important role in some organisms as it helps to convert light into metabolic energy.

Opsins are the light sensitive proteins which help in vision and are found in photoreceptor cells of the retina. There are five classical groups of opsins which are involved in vision, mediating the conversion of a photon of light into an electrochemical signal which is carried to the brain. This is the first step in the visual transduction cascade. The absorption spectrum of the chromophore depends on its interaction with the opsin protein to which it is bound.

Hence, the correct answer is option (A).

Note: The photosensitive compound present in vision is called rhodopsin and it consists of protein called opsin and retinal. Retinal also helps in converting light into metabolic energy in some micro-organisms which help them in fulfilling their energy requirements.