WANI Dictionary

Lipid

Lipids are water-insoluble biomolecules that are soluble in organic solvents.

However, Molecules categorized as “lipids” may vary depending on contexts and historical perspectives. Lipids typically include following groups of molecules:

• Triacylglycerols (fats and oils)
• Fatty acids with a long hydrophobic chain
• Waxes
• Phospholipids
• Steroids and polyisoprenoids

While carotenoids have similar water solubility to steroids, they are not commonly classified as lipids because historically they have been considered “pigments”.

Definitions in the literature

• Lipids are defined as the water-insoluble molecules in cells that are soluble in organic solvents [1].
• Any of a diverse group of organic compounds, occurring in living organisms, that are insoluble in water but soluble in organic solvents, such as chloroform, benzene, etc. [2].
• By definition, lipids are water-insoluble biomolecules that are highly soluble in organic solvents such as chloroform [3].
• Lipids are fatty, waxy, or oily compounds that are soluble in organic solvents and insoluble in polar solvents such as water. Lipids include: Fats and oils (triglycerides), Phospholipids, Waxes, Steroids [4].