1. Lipids encompass a large and diverse group of organic compounds 1.1 Lipids are broadly defined as biological molecules that are soluble in organic solvents. 1.1.1 Lipids are usually extracted from biological materials by nonpolar solvents like ether, chloroform(氯仿), benzene(苯). 1.2 The biological functions of lipids are diverse. 1.2.1 Certain lipids(e.g., triacylglycerols(三脂酰甘油), commonly called fats) serve as efficient reserves for the storage of energy