Question

Describe the functions of the four photoreceptor proteins in human vision.

Answer 1

Answer:

In human vision, the cone visual opsins are grouped into four photoreceptor protein families LWS, SWS1, SWS2, RH2 .

• SWS1: produce pigments sensitive to very short wavelengths, UV-violet, 360-450 nm.

• SWS2: produce pigments sensitive to short wavelengths, blue, 450-495 nm

• RH2: produce pigments sensitive to medium wavelengths, green, 495-560 nm

• LWS: produce pigments sensitive to long wavelengths, yellow-red, 560-770nm.

Explanation:

Photoreceptor proteins are light-sensitive proteins that mediate light-induced signal transduction, thus they are involved in the sensing and response to light in a variety of organisms.

The photoreceptor proteins are classified based on the chemical structure of the chromophores involved, the light absorption and on the protein sequence.

This photoreceptor proteins are located at the cone photoreceptor cells and are responsible of photopic vision.

For scotopic vision, rhodopsin is responsible. Rhodopsins are the visual pigments (visual purple) of the rod photoreceptor cell in the retina. They are responsible of human vision in dim light, as it contains a sensory protein that converts light into an electric signal.