Chapter 5 Lipids Lipids a family of compounds that include triglycerides phospholipids and sterols They are characterized by the insolubility in water Linoleic Acid an essential fatty acid with 18 carbons and two double bonds Linolenic Acid essential fatty acid with 18 carbons and THREE double bonds Omega refers to the position of the closests double bond to the methyl end of a fatty acid Omega 3 Fatty Acid Polyunsaturated Fatty acid in which the closest double bond to the methyl end of the carbon chain is 3 carbons away Omega 6 Fatty Acids Polyunsaturated Fatty acid in which the closest double bond to the methyl end of the carbon chain is 6 carbons away Triglycerides Chief form of fat in the diet and the major storage form of fat in the body composed of a molecule of glycerol with 3 fatty acids attached Glycerol An alcohol composed of a 3 carbon chain which can serve as the backbone for a triglyceride Condensation Chemical reaction in which water is released as 2 molecules combine to form one larger product Fats lipids that are solid at room temp Oils Lipids that are liquid at room temp Oxidation process of a substance combining with oxygen oxidation reactions involve the loss of electrons Antioxidants As a food additive preservatives that delay or prevent rancidity of fats in foods and other damage to food cause by oxygen Hydrogenation Chemical process by which hydrogens are added to monosaturated or polyunsaturated fatty acids to reduce the number of double bonds making the fats more saturated and more resistant to oxidation Produces trans fatty acids Cis refers to the chemical configuration in which the hydrogen atoms are located on the same side of a double bond Trans refers to the chemical configuration in which hydrogen atoms are located on opposite sides of a double bond Trans Fatty Acids Fatty acids with hydrogens on opposite sides of the double bond Conjugated Linoleic Acids Several fatty acids that have the same chemical formula as linoleic acid but with different configurations Phospholipids Compound similar to a triglyceride but having a phosphate group and choline in place of one of the fatty acids Lecithin One of the phospholipids Both nature and the food industry use lecithin as an emulsifier to combine water soluble and fat soluble ingredients that do not ordinarily mix such as water and oil Choline A nitrogen containing compound found in foods and made in the body from the amino acid methionine It is part of the phospholipid lecithin and the neurotransmitter acetylcholine Hydrophobic water fearing or non soluble substances also known as lipophilic fat loving Hydrophilic water soluble or water loving Emulsifiers Substances with both water soluble and fat soluble portions that promote the mixing of oils and fats in watery solutions Sterols Compounds containing a four ring carbon structure with any of a variety of side chains attached Cholesterol One of the sterols containing a four ring carbon structure with a carbon side chain Endogenous from within the body Exogenous From outside the body Plaque Buildup of fatty deposits smooth muscle cells and fibrous connective tissue that develops in the artery walls in atherosclerosis Plaque associated with atherosclerosis is known as athermanous plaque Atherosclerosis A type of artery disease characterized by plaque on the inner walls of the arteries Lipases Enzymes that hydrolyze lipids Lingual lipase refers to the fat digesting enzyme secreted from the salivary gland at the base of the tongue Monoglycerides Molecules of glycerol with one fatty acid attached A molecule of glycerol with 2 fatty acids attached is a diglyceride Micelles Tiny spherical complexes of emulsified fat that arise during digestion most contain bile salts and the products of lipid digestion Including fatty acids monoglycerides and cholesterol Lipoproteins Clusters of lipids associated with proteins that serve as transport for lipids in the lymph and blood Chylomicrons Class of lipoproteins that transport lipids from the intestinal cells to the rest of the body VLD Very low density lipoproteins Type of lipoprotein made primarily by liver cells to transport lipids to various tissues in the body composed primarily of triglycerides LDL Low Density Lipoprotein Type of lipoprotein derived from VLDL as triglycerides are removed and broken down composed primarily of cholesterol Bad HDL High Density Lipoprotein Type of lipoprotein that transports cholesterol back to the liver from the cells composed primarily of protein Good Adipose Tissue The body s fat tissue consists of masses of triglyceride storing cells Adipokines Proteins synthesized and secreted by adipose cells Essential Fatty Acids Fatty acids needed by the body but not made by it in amounts sufficient to meet physiological needs Arachidonic Acid An Omega 6 polyunsaturated fatty acid with 20 carbons and 4 double bonds present in small amounts in meat and other animal products synthesized in the body from linoleic acid Conditionally Essential Nutrient A nutrient that is normally non essential but must be supplied by the diet in special circumstances when the need for it exceeds the body s ability to produce it Eicosapentaenoic Acid Omega 3 polyunsaturated fatty acid with 20 carbons and 5 double bonds present in fatty fish and synthesized in limited amounts in the body from linolenic acid Docosahexaenoic Acid Omega 3 polyunsaturated fatty acid with 22 carbons and 6 double bonds present in fatty fish and synthesized in limited amounts in the body from linolenic acid Eicosanoids Derivatives of 20 carbon fatty acids biologically active compounds that help to regulate blood pressure blood clotting and other body functions They include PROSTAGLANDINS THROMBOXANES and LEUKOTRIENES Lipoprotein Lipase LPL Enzyme that hydrolyzes triglycerides passing by in the bloodstream and directs their parts into the cells where they can be metabolized for energy or reassembled for storage Hormone Sensitive Lipase Enzyme inside adipose cells that responds to the body s need for fuel by hydrolyzing triglycerides so that their parts escape into the general circulation and thus become available to other cells for fuel The signals to which this enzyme responds include epinephrine and glucagon which oppose insulin Blood Lipid Profile results of blood tests that reveal a person s total cholesterol triglycerides and various lipoproteins Cardiovascular Disease Disease of heart and blood vessels throughout the body Atherosclerosis