<p> Work Sheet 12</p><p>Overview of Nutrients 1. Define: essential nutrient, protein quality, ideal protein, essential amino acid, vitamin. Essential Nutrient: substance which must be provided for everyone at every age for health maintenance.</p><p>Essential amino acids- cannot be synthesized by the body and must be obtained in the diet. (Arg, His, Ile, Leu, Lys, Met, Phe, Thr, Trp, Val)</p><p>Non-essential amino acids- can be synthesized by the body.</p><p>"Ideal protein"- would have an amino acid composition that provides the exact balance of amino acids required for the normal adult.</p><p>Biological Value- measure of the ability of a protein to provide essential amino acids to tissues, ability to be successfully digested.</p><p>2. List the forms and identifying characteristics of each of the forms of malnutrition.</p><p>1. Obesity- caloric intake in excess of expenditure.</p><p>Risks: cardiovascular disease, hypertension and diabetes.</p><p>2. Nutritional imbalance-overconsumption of one or more nutrients.</p><p>Risks: not many, but remember L-Trp.....</p><p>3. Undernutrition:</p><p>(a) Protein-calorie malnutrition-inadequate nourishment</p><p>Risks: starvation</p><p>(b) Kwashiorkor-diet with a low protein/energy ratio, usually based on corn</p><p>Risks: failure to thrive and develop 3. List and define the energy providing nutrients, their major functions in the body and the number of calories (Kcal) furnished by each.</p><p>1. Carbohydrates: C, H and O, provide 4 Kcal/g and are the major energy source for the world's population.</p><p>(a) Available Carbohydrates: starch in plants and glycogen in animals.</p><p>In the human diet- starch, sucrose and lactose are the most important available dietary carbohydrates.</p><p>(b) Unavailable Carbohydrates: fiber</p><p>Complex plant material comprised primarily of cellulose, lignin and pectins that resist digestion in the human body.</p><p>2. Proteins: provides 4 Kcal/g and furnish essential amino acids for the synthesis of body proteins.</p><p>3. Lipids: consist primarily of C and H</p><p>(a) Triacylglycerols (triglycerides)- body's main energy source, 9 Kcal/g. Storage form of fat for fuel in the body, 95-98% of ingested fat from food is stored in adipose cells.</p><p>(b)Phospholipids- ingested in small amounts and present in the body as constituents of cell membranes.</p><p>(c) Sterols</p><p>4. Ethanol is unique among dietary caloric sources in addition to providing a source of energy it has potent pharmacological and biochemical properties. Ethanol furnishes 7 Kcal/g, over 90% of ingested ethanol is metabolized in the liver through oxidation.</p><p>4. Discuss the significance of ethanol as fuel and low vs. high alcohol intake.</p><p>Ethanol is unique among dietary caloric sources in addition to providing a source of energy it has potent pharmacological and biochemical properties. Ethanol furnishes 7 Kcal/g, over 90% of ingested ethanol is metabolized in the liver through oxidation.</p><p>Risks: calories consumes as ethanol in excess of daily requirements are deposited as fat..... at high doses (> 50% of calories) ------> weight loss, water soluble vitamin deficiencies, interference with metabolic pathways, reduced liver function. 5. For each of the 9 water soluble vitamins, list: (a) major function(s) (b) RDA (recommended daily allowance).</p><p>See Table in lecture notes.</p><p>Vitamins of Carbohydrate and Nitrogen Metabolism 1. Explain how nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+) containing enzymes function in energy producing pathways.</p><p>How Does NAD+ Work as an Electron Carrier:</p><p>2. Explain how flavin adenine dinucleotide (FAD) containing enzymes function in energy producing pathways.</p><p>How Does FAD Work as an Electron Carrier: 3. List key metabolic pathways in which NAD+, NADP+ and FAD participate.</p><p>NADH Key Metabolic Pathways: glycolysis, citric acid cycle, respiratory chain, amino acid metabolism FADH2 Key Metabolic Pathways: amino acid deamination, purine degradation, citric acid cycle, fatty acid oxidation</p><p>4. Compare and contrast dietary and metabolic sources of niacin and riboflavin.</p><p>Metabolic Sources of NAD+:</p><p>Tryptophan is converted to NAD+.</p><p>Metabolic Sources of FAD:</p><p>Not synthesized by mammals.</p><p>5. Identify the key metabolic pathways in which vitamin B6 dependent enzymes participate. Key Metabolic Pathways: glycogenolysis, transamination, decarboxylation</p>