Lipids are biomolecules which are soluble in organic non-polar solvents. Consequently, fats and lipids are insoluble in water. Glycerides and waxes form a sub-group of compounds which have an ester as...Lipids are biomolecules which are soluble in organic non-polar solvents. Consequently, fats and lipids are insoluble in water. Glycerides and waxes form a sub-group of compounds which have an ester as the major functional group and include: waxes, triglycerides, and phospholipids. Another diverse group of compounds which do not have any ester functional groups are also classified as lipids including: steroids, fatty acids, soaps, sphingolipids, and prostaglandins.