Why hydrolysis of visual purple is written in option B. Hydrolysis of CGMP occurs in light state

why hydrolysis of visual purple is written in option B. Hydrolysis of CGMP occurs in light state

In the context of vision, visual purple refers to a pigment called rhodopsin, which is found in the rods of the retina. Rhodopsin undergoes a process called bleaching when exposed to light. This process involves the hydrolysis of a molecule called cyclic guanosine monophosphate (cGMP) to its constituent parts, resulting in a change in the electrical potential of the rod cell.

The hydrolysis of cGMP occurs in the light state, not the dark state. When rhodopsin absorbs light, it undergoes a conformational change, which activates an enzyme called phosphodiesterase. This enzyme catalyzes the hydrolysis of cGMP, leading to a decrease in its concentration in the rod cell. The decrease in cGMP levels causes the closure of ion channels, hyperpolarization of the cell membrane, and ultimately the transmission of the visual signal to the brain.

Therefore, the correct statement would be: “Hydrolysis of cGMP occurs in the light state.”