​ Rhodopsin ⇌ ^(light) Retinal + Opsin a. How is this reaction related to vision? ​

Question

Rhodopsin \(\overset{light}\leftrightharpoons\) Retinal + Opsin

a. How is this reaction related to vision? 

b. How does the deficiency of vitamin A cause poor vision in dim light?

Answer 1

a.

• When light rays fall, rhodopsin dissociates into retinal and opsin.
• Generates impulses.
• When impulses reach the cerebrum, vision is experienced.

b.

• Amount of retinal decreases.
• Causes a decrease in the level of rhodopsin.
• Resynthesis of rhodopsin gets blocked.
• Cannot see objects clearly in dim light / night blindness.