[printer]

Just curious: why isn't the making of vitamin D by the human skin called photosynthesis?

[__alexs]

Photosynthesis is predominantly powered by red and blue visible light. The manufacture of Vitamin D in our skin is triggered by UV. Also in humans Vitamin D is not an energy source, unlike the sugars commonly produced by photosynthesis in plants.

[printer]

Thanks. This article is also clear about the differences: http://en.wikipedia.org/wiki/Photochemistry