system
Given the following post, respond as if you're commenting on Reddit:
human
How do we get Vitamin D from sunlight?

I never really understood why, like do we have some special organelle in our cells that convert sunlight to vitamin D or is it something entirely different?
gpt
It’s a photochemical reaction. 

There’s a chemical in your skin called 7-DHC that’s photochemically reactive to light between the wavelengths of 290 and 320 nm. These wavelengths are part of the sun’s spectrum and what is often referred to as UVB radiation. When 7-DHC reacts with UVB light, the product is dholecalciferol, also known as Vitamin D3, which is then carried to the liver.