Triacylglycerol and Lipid Classification

Triacylglycerol (TAG)

• Triacylglycerols (TAGs) are neutral fats, a type of simple lipid.
• TAGs consist of a glycerol backbone with three fatty acids attached.
• Glycerol backbone has a chemical structure CH₂OH-CHOH-CH₂OH

TAG Classification

• TAGs are categorized into oils and fats.
• Oils are liquid at room temperature due to high unsaturated fatty acid (USFA) content. Examples include corn oil, cottonseed oil, and soybean oil.
• Fats are solid at room temperature with a high saturated fatty acid (SFA) content. Examples include margarine.

Hardening of Oils

• Hardening is the hydrogenation of oils to create solid fats like margarine. This process converts unsaturated fatty acids to saturated fatty acids.

Phospholipids

• Phospholipids are compound lipids.
• Classification is based on the alcohol present.
• Phosphoglycerides contain glycerol.
• Sphingomyelin contains sphingosine.

Phosphoglycerides

• Phosphatidic acid
• Lecithin (phosphatidylcholine)
• Cephalin (phosphatidylethanolamine)
• Phosphatidylserine
• Phosphatidylinositol

Sphingomyelin

• Sphingomyelin differs from other phospholipids by containing sphingosine instead of glycerol.

Ceramide Structure

• Ceramide is a component of sphingomyelin.
• It consists of sphingosine and a fatty acid.

Phospholipid Importance

• Amphipathic molecules (both polar and nonpolar parts).
• Form micelles in water.
• Good emulsifying agents aiding in fat digestion.
• Essential constituents of cell membranes.
• Components of plasma lipoproteins (lipid carriers in the blood).

Lysophospholipids

• Formed by the action of phospholipase A2 on lecithin or cephalin.
• Phospholipase A2 removes a fatty acid from position 2.

Snake Venom

• Contains lecithinase enzymes.
• When injected into blood converts phospholipids in red blood cell membranes into lysophospholipids.
• Leads to red blood cell lysis and potential death if not treated.

Steroids

• Steroids are categorized into sterols, bile acids, and steroid hormones.
• Sterols include cholesterol.
• Bile acids aid in fat digestion and absorption.
• Steroid hormones include glucocorticoids, mineralocorticoids, and sex hormones.

Bile Acids

• Primary bile acids are synthesized from cholesterol in the liver.
• Secondary bile acids are formed by intestinal bacteria acting on primary bile acids.
• Bile acids are conjugated with glycine or taurine, and sodium; then secreted as bile salts.

Bile Salts Function

• Bile salts are important for emulsifying fats.
• This aids in the digestion and absorption of fats.

This quiz covers the fundamentals of triacylglycerols (TAGs) and their classification into oils and fats. It also explores the hydrogenation process of oils, leading to the formation of solid fats like margarine, and delves into phospholipids and their types, such as phosphoglycerides. Test your knowledge on these key concepts in lipid chemistry!