Vitamin D₃ Photosynthesis in Skin

7-Dehydrocholesterol → Previtamin D3 → Vitamin D3

Übersicht

UV-B radiation (280–315 nm) converts 7-dehydrocholesterol in the skin to previtamin D₃ through a photochemical ring-opening reaction. Previtamin D₃ then thermally isomerizes to cholecalciferol (vitamin D₃). This is the primary source of vitamin D for most people and requires about 10–30 minutes of midday sun exposure.

Alltägliches Beispiel

Spending 15–20 minutes in midday sunshine produces about 10,000–20,000 IU of vitamin D₃, far more than any food source.

Industrielle Bedeutung

Vitamin D deficiency affects over 1 billion people worldwide, driving demand for supplements and UV-fortified foods.

Eigenschaften

Typ
Photochemical
Reversibel
Nein
Energie
Endotherm

Verwandte Reaktionen

Photochemical Smog Formation (NO₂ Photolysis) Photochromism of Spiropyran Chlorophyll Fluorescence Photodegradation of Methylene Blue by TiO₂ Photodissociation of Chlorine Gas Silver Bromide Photodecomposition Cis-Trans Isomerization of Retinal Photosynthesis Ozone Formation by UV Light Dye-Sensitized Solar Cell (Grätzel Cell)

Frequently Asked Questions

What is the equation for Vitamin D₃ Photosynthesis in Skin?
The balanced equation is: 7-Dehydrocholesterol → Previtamin D₃ → Vitamin D₃.
What type of reaction is Vitamin D₃ Photosynthesis in Skin?
Vitamin D₃ Photosynthesis in Skin is a photochemical reaction.
Is Vitamin D₃ Photosynthesis in Skin exothermic or endothermic?
Vitamin D₃ Photosynthesis in Skin is endothermic (absorbs energy).