Vitamin D₃ Photosynthesis in Skin

7-Dehydrocholesterol → Previtamin D₃ → Vitamin D₃

Tổng quan

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.

Ví dụ thực tế

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

Tầm quan trọng công nghiệp

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

Tính chất

Loại: Photochemical
Thuận nghịch: Không
Năng lượng: Thu nhiệt

Phản ứng liên quan

Cis-Trans Isomerization of Retinal Silver Chloride Photodecomposition Luminol Chemiluminescence Firefly Bioluminescence (Luciferin Oxidation) Photolysis of Water (Vacuum UV) Photochemical Smog Formation (NO₂ Photolysis) Photodegradation of Methylene Blue by TiO₂ Photodissociation of Chlorine Gas Silver Bromide Photodecomposition Chlorophyll Fluorescence

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).