Types of Triacylglycerols - Structures and Properties

Lipids

• Lipids are a family of substances that are insoluble in water but soluble in nonpolar solvents and solvents of low polarity, such as diethyl ether.
• Classification of lipids by function: storage, membrane components, and messenger.

Classification of Lipids

• By function: storage, membrane components, and messenger.
• By structure: simple lipids (fats, oils, and waxes), complex lipids, steroids, prostaglandins, thromboxanes, and leukotrienes.

Triglycerides

• Triglycerides are triesters of glycerol and long-chain carboxylic acids called fatty acids.
• Two types of triacylglycerols: simple triacylglycerols (rare) and mixed triacylglycerols (most common).
• Example of a simple triacylglycerol and a mixed triacylglycerol.

Properties of Triglycerides

• Physical state: triglycerides can be solid (fats) or liquid (oils) at room temperature.
• Saponification: base-promoted hydrolysis of fats and oils producing glycerol and a mixture of fatty acid salts called soaps.

Complex Lipids

• Schematic diagram of simple and complex lipids.
• Complex lipids include phospholipids, glycolipids, and lipoproteins.

Role of Lipids in the Structure of Membrane

• Lipids are components of biological membranes.
• Fatty acids, glycerides, and phospholipids are important for membrane structure.

Classification of Lipids based on Polarity

• Nonpolar lipids: fats, oils.
• Polar lipids: phosphoacylglycerols, sphingolipids.
• Non-fatty acid lipids: terpenes, fat-soluble vitamins.

Types of Fatty Acids

• Saturated fatty acids: have a carbon chain with all single C-C bonds.
• Unsaturated fatty acids: have one or more C-C double bonds.
• Polyunsaturated fatty acids (PUFAs): have multiple C-C double bonds.
• Omega (ω)-3 and omega (ω)-6 fatty acids.