BIOCHEMISTRY - Textbook - Ostapchenko L. I. - 2012

Chapter 13. STRUCTURE AND PROPERTIES OF LIPIDS

Lipids are structurally diverse natural Organic compounds—derivatives of Higher Fatty acids, alcohols, and aldehydes—whose defining characteristic is Structure/106.html">Hydrophobicity. Lipid molecules are present in the Cells of microorganisms, plants, and animals, where they perform a variety of Functions. Lipids serve as major Structural components of Cell membranes, and their content in cellular Organelles can reach up to 60% of the dry weight of these structures. They also act as a reserve energy substrate, and function as thermomechanical protective barriers for animal Tissues and Organs, among other roles.

Based on their chemical structure and physicochemical properties, lipids are divided into three classes:

✵ neutral lipids—derivatives of glycerol and higher fatty acids, alcohols, and aldehydes, whose molecules lack charged (ionized) or polar groups;

✵ Phospholipids—derivatives of phosphatidic acid and amino alcohols, Amino Acids, and polyhydric alcohols;

✵ Sphingolipids—derivatives of the amino alcohol sphingosine, higher fatty acids, and sugars. The hydrophilic components of these lipid molecules can include phosphorylcholine and phosphorylethanolamine.