Steroids: Derived lipids

Lipids are biological molecules that are insoluble in water but soluble in nonpolar solvents. Lipids are widely distributed in nature and present in both plants and animals. There are four main groups of lipids include:
*Fatty acids (saturated and unsaturated)
*Glycerides (glycerol-containing lipids)
*Nonglyceride lipids (sphingolipids, steroids, waxes)
*Complex lipids (lipoproteins, glycolipids)

Steroids are classified as lipids because they are soluble in nonpolar solvents, but they are nonsaponifiable because the components are not held together by ester linkages.

Some common steroids are:
*Cholesterol, ergosterol: present in plants and yeast, a precursor of vitamin D
*Coprosterol: occurs in feces, derived in the intestine by bacterial action on dietary cholesterol
*Lanosterol: It is a major constituent of wool fat and is also present in minor quantities in liver and yeast
*Terpenes: Among the non-saponifiable lipids found in plants

Cholesterol is the most abundant steroid in the body. It is an essential component of cell membranes, and is a precursor for other steroids, such as the bile salts, sex hormones, vitamin D, and the adrenocorticoid hormones.
Steroids: Derived lipids