steroids

Biosynthesis of Steroids

Definition  

 A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes which alter membrane fluidity; and as signaling molecule.

Classification

•     Sterols
•     Bile acids
•     Vitamin D
•     Male sex hormones
•     Female sex hormones

Structure

Composed of: seventeen carbon atoms, bonded in four "fused" rings: three six-member cyclohexane rings

Function 

steroids have two principal biological functions:Important components of cell membranes which alter membrane fluidity Act as signaling molecules.Biosynthesis of sterols

Biosynthesis of cholesterol

Synthesis of mevalonate from acetate 

Conversion of Mevalonate to Two Activated Isoprenes 

Condensation of Six Activated Isoprene Units to Form Squalene

Conversion of Squalene to the Four-Ring Steroid Nucleus

Biosynthesis of Vitamin D