Lipids are biomolecules soluble in non-polar p的a onhcoand hophoi o0nreEasaaanecnasAa med alkanamides,cylic amidesar -c is replaced by -amide Lipid bilayers are the basic components of cell membranes NR RN-C 7 7 Fats: •Biological energy reserves •Solvents for food flavors and colors •Contribute to feeling of “fullness” after eating •Implicated in atherosclerosis when containing the saturated fatty acids hexadecanoic-, tetradecanoic- and dodecanoic￾acids •(Z)-9-octadecenoic (oleic) acid found in olive oil implicated in low rates of heart disease Lipids are biomolecules soluble in non-polar solvents. Non-polar solvent extracts a wide range of non-polar substances from biological materials: terpenes, steroids, fats, oils and other lipids, such as phospholipids. Phospholipids are important components of cell membranes. Lecithin is a phosphoglyceride lipid found in the brain and central nervous system. Long-chain carboxylic acids and phospholipids are termed amphipathic: they have hydrophobic and hydrophilic ends. When dissolved in water, fatty acids and some phospholipids form structures called “micelles.” Most phospholipids form a more complicated structure called a “lipid bilayer” when dissolved in water. Lipid bilayers are the basic components of cell membranes. Amides: The Least Reactive Carboxylic Acid Derivatives 20-6 Amides are named alkanamides, cyclic amides are lactams. Amides are called alkanamides, the –e in alkane having been replaced by –amide. In the common names, -ic is replaced by –amide. In cyclic systems, –carboxylic acid is replaced by –carboxamide. Nitrogen substituents are indicated by the prefix N- or N,N-. Amides can be primary, secondary or tertiary. Derivatives of carbonic acid, H2CO3, include ureas, carbamic acids and carbamic esters. Cyclic amides are called lactams. The systematic name is aza-2- cycloalkanones. The naming rules follow those used for lactones