HUMN NTR 2210 Study Guide Chapter 5 Lipids 1 What is the structure of a triglyceride 1 Glycerol and 3 fatty acids glycerol small 3 carbon carbohydrate backbone fatty acids chain of carbons with hydrogens H H H H C fatty acid C fatty acid C fatty acid H 2 What is the chemical difference between saturated and unsaturated fatty acids saturated fatty acid contains no carbon carbon double bond while unsaturated fats do saturated fatty acid filled with hydrogens solid unsaturated has some hydrogens missing 3 What is a polyunsaturated fatty acid a fatty acid containing 2 or more carbon carbon double bonds even less saturated with hydrogens ex omega 3 and omega 6 both essential nutrients 4 Why are polyunsaturated fats more likely to spoil or become rancid What can be done to reduce this spoilage because they have more carbon carbon double bonds so when they break down they produce rancid by products if you have less then you have less by products to reduce add antioxidants such as vitamin E BHA BHT hydrogenation 5 What are hydrogenated oils hydrogenation make unsaturated fatty acids more saturated used to solidify an oil addition of hydrogen to carbon carbon bonds oils made solid for better use examples margarine shortening Crisco easy to handle and store high smoking point good for frying produces trans fatty acids 6 What are trans fats What are the health dangers of excessive trans fat intake How can we minimize our intake of trans fat trans fats form of unsaturated fatty acid usually monounsaturated one when found in food in which the hydrogens on both carbons forming the double bond lie on opposite sides of the bond by product of hydrogenation increases the risk of heart disease increase overall inflammation in the body required on food labels limit use of hydrogenated fats limit deep fried foods limit high fat baked goods limit use of non dairy creamers read labels for trans fat 7 What is a monounsaturated fatty acid What oils or foods are good sources of monounsaturated fatty acids a fatty acid containing one carbon carbon double bond canola and olive oils avocados nuts 8 9 What is the difference between an omega 3 and an omega 6 fatty acid What is the name of the essential fatty acid in each of these categories omega 3 an unsaturated fatty acid with the first double bond being on the third carbon from the methyl end alpha linolenic acid omega 6 an unsaturated fatty acid with the first double bond being on the sixth carbon from the methyl end linoleic acid Relate the need for omega 3 fatty acids in the diet to the recommendation to consume fish twice a week How much cold water fish should we consume to get the correct amount of omega 3 fatty acids compounds made from these tend to decrease blood clotting and inflammatory processes in the body studies show that people who eat fish twice a week run lower risks of heart attack caused by clotting than people who rarely eat fish omega 3 fatty acids are in fish oil causing this So the risk of heart attack decreases with the consumption of omega 3 fatty acids from fish 3 6 ounces per week about 1 gram a day 10 What are eicosanoids What effects do they have on the body Eicosapentaenoic acid is metabolized into eicosanoids this ia an omega 3 fatty acid with 20 carbons an 5 carbon carbon double bonds present in large amounts in fatty fish and is slowly synthesized in the body from alpha linolenic acid control inflammation or immunity fever regulation of blood pressure blood clotting immune system modulation control of reproductive processes and tissue growth and regulation of the sleep wake cycle 11 What are phospholipids class of lipids built on backbone of glycerol made up of glycerol 2 fatty acids and phosphorous compound exist especially in the brain synthesized by body made easily What important roles do they play in body components and foods form important parts of cell membranes participate in fat digestion absorption and transport found widely in food used in food as an emulsifier improves food products What is an emulsifier compound that can suspend fat in water by isolating individual fat droplets using a shell of water molecules or other substances to prevent the fat from coalescing example lecithin common phospholipids 12 How does the structure of sterols differ from other lipids carbons are arranged in a multi ringed structure ex cholesterol 13 What are the important functions of cholesterol used to form certain important hormones building block of bile acids need for fat digestion and is essential structural component of cells and outer layer of lipoprotein particles 14 Why is cholesterol also considered to be bad for you if you have low HDL high density lipoprotein in the bloodstream little cholesterol is transported back to the liver and excreted increasing the risk of cardiovascular disease if you have high LDL low density lipoproteins in the bloodstream then it causes a buildup of cholesterol in the blood vessels atherosclerosis which leads to an increased risk for cardiovascular disease 15 What are some of the major dietary sources of cholesterol animal derived food products eggs and oils meat and poultry snack foods and processed foods dairy products 16 Describe the fat substitutes that are used in reduced fat foods have 0 75 less fat than in the original food usually sugar is added in place of fat may replace fat with water protein Dairy Lo or forms of carbohydrates such as starch derivatives Z Trim fiber Maltrin Stellar Oatrim and gums also may use engineered fats such as Olestra 17 Describe the important steps enzymes and other important components of fat digestion first phase stomach releases lipase fat digesting enzyme produced by the salivary glands stomach and pancreas digest short and medium chain fatty acids pancreas lipase strongest long chain fatty acids not digested in stomach digestion then moved to small intestine which is the primary site of fat digestion lipase breaks down triglycerides into smaller products named monoglycerides and fatty acids under the right circumstances digestion is rapid and thorough include the prescence of bile from gallbladder bile acids act as emulsifiers and improve digestion and absorption because large fat broken down total surface area for lipase action increases 18 Describe the structures origins and roles of the four major blood lipoproteins Chylomicrons made of dietary fats surrounded by shell of cholesterol phospholipids and protein formed in the absorptive cells of the
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