Lipid Classification Cheat Sheet

Lipids are a diverse group of molecules essential for biological functions, including energy storage, structural integrity, and signaling. They are broadly classified into fatty acids, glycerol lipids, sphingolipids, sterols, and terpenes, each with unique structures and roles.

Core Principles

• Fatty acids are carboxylic acids with hydrocarbon chains, varying in length and saturation, and can be short, medium, or long chain.
• Glycerol lipids, such as triacylglycerols (TAGs), are crucial for energy storage and are formed by esterifying fatty acids to glycerol.
• Phospholipids, a type of glycerol lipid, are key components of cell membranes due to their amphipathic nature.
• Sphingolipids utilize sphingosine as a backbone instead of glycerol and are important membrane components, particularly in the central nervous system.
• Sterols, like cholesterol, have a characteristic four-ring structure and are vital for membrane fluidity, hormone synthesis, and bile acid production.
• Terpenes are derived from isoprene units and are known for their aromas, acting as plant defense mechanisms and having industrial and medicinal applications.

Formulas

• $R-COOH + R-OH \rightarrow R-COO-R + H_2O$

Quiz

• Which type of fatty acid has no carbon-carbon double bonds?: Saturated fatty acid
• What is the primary function of Triacylglycerol (TAG)?: Energy storage
• Cholesterol is a type of:: Sterol