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156 Cards in this Set
- Front
- Back
What are essential nutrients?
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Nutrients that cannot be synthesized by body cells and must be ingested in diet.
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How are carbohydrates usually obtained?
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From plant products.
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How are monosaccharides primarily used?
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As cellular fuel.
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What is ATP?
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Chemical energy form used by cells.
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What are the primary sources of saturated fats?
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Animal products
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What are the primary sources of unsaturated fats?
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Plant products
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What ar the primary sources of cholesterol?
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Egg yolks, meats, milk products
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What are the functions of neutral fats?
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To reserve energy, cushion body organs, and insulate body.
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How is cholesterol used?
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In plasma membranes and is the structural basis of vitamin D, steroid hormones, and bile salts.
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What is the recommended percentage for caloric intake of fats?
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30 percent or less.
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What is the recommended intake of cholesterol?
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250 mg. or less.
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What requirements must be met for protein synthesis to occur?
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All essential amino acids must be present and sufficient carbohydrat (or fat) calories available to produce ATP.
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What is the recommended caloric intake range?
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1500 - 2800 calories daily.
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What are the 6 categories of the food pyramid from top to bottom?
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Fats, Dairy, Proteins, Veggie, Fruits, Carbohydrates
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What is Glucose?
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Monosaccharide that is a major body fuel and is readily used to make ATP.
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Which vitamins are made in the body?
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Vitamins B, D, K.
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Which vitamins are fat soluble?
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Vitamins A, D, E and K
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Which vitamin is incapable of being stored in toxic amounts?
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Vitamin K.
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What are some minerals that must be present in the body in trace amounts?
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Calcium, Chloride, Magnesium, Phosphorus, Potassium, Sulfur, Sodium.
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What are some uses of minerals in the body?
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Mineralize bone, exist as ions in body fluids where they play various roles in cell processes and metabolism.
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What are the richest sources of minerals?
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Animal products, vegetables and legumes.
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What are the 2 categories of metabolic processes?
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Anabolic or catabolic
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What is cellular respiration?
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Catabolic processes during which energy is released and some is captured in ATP bonds.
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When is energy released?
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When organic compounds are oxidized.
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How is glucose oxidized to carbon dioxide and water?
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Glycolysis, Krebs cycle, and electron transport chain.
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What happens when cellular ATP reserves are high?
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Glucose catabolism is inhibited and glucose is converted to glycogen (glycogenesis) or to fat (lipogenesis).
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What is gluconeogenesis?
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Formation of glucose from noncarbonhydrate (fat or protein) molecules. Occurs in liver when blood glucose levels begin to fall.
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What is lipolysis?
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Breakdown of fats to fatty acids and glycerol.
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What happens when the body uses excessive amounts of fats?
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Liver converts acetyl CoA to ketone bodies and releases them to blood.
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All cells use two ingredients to build their plasma membranes. Name them.
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Phospholipids, cholesterol.
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What conversion does amino acids undergo to be oxidized for energy?
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Amino acids are converted to keto acids that can enter the Krebs cycle.
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What are the body's most important building blocks?
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Amino acids.
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How is urea formed?
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Amine groups removed during deamination combine with carbon dioxide by the liver to form urea.
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What is the postabsorptive state?
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Period when bloodborne fuels are provided by breakdown of energy reserves.
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How are events of the postabsorptive state controlled?
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By glucagon and the sympathetic nervous system, which mobilize glycogen and fat reserves and trigger gluco-neogenesis.
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What are some functions of the liver?
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It helps maintain blood energy sources, metabolizes hormones, and detoxifies drugs and other substances.
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How does obesity occur?
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When excess amounts of energy are stored, 20% or more above norm.
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What is the metabolic rate?
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Body's rate of energy output.
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What is the basal metabolic rate (BMR)?
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Energy the body needs to perform only essential activities (breathing, rest).
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What factors influence metabolic rate?
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Age, sex, size, body surface area, thyroxine levels, dynamic action of foods, muscular activity.
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When the body is at rest, what organs generate body heat?
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Liver, heart, brain, kidneys, endocrine organs.
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What parts of the body has the highest temperature?
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Body core (organs with skull and ventral body cavity).
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What are some heat-exchange mechanisms?
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Radiation, conduction, convection and evaporation.
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What organ is the body's thermostat?
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Hypothalamus.
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What are some heat-promoting mechanisms?
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Constriction of skin vasculature, increase in metabolic rate, shivering.
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What are the most abundant dietary lipids?
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Neutral fats (triglycerides aka triacyglycerols).
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What is a nutrient?
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Substance in food that is used by body to promote normal growth, maintenance, and repair.
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What are the six categories of nutrients?
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Carbohydrates, lipids, proteins, vitamins, minerals, water.
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What is glucose?
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Carbohydrate molecule used by body as fuel to make ATP.
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What is the current recommendation of carbohydrate consumption per day?
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125 - 175 grams with emphasis on complex carbohydrates.
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What are the most common dietary lipids?
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Neutral fats, triglycerides
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Why are dietary fats essential?
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Major source of fuel for hepatocytes and skeletal muscle, absorption of fat-soluble vitamins, components of myelin sheaths and cellular membranes of body.
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Define dehydrogenases.
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Enzymes that catalyze redox reactions where hydrogen atoms are removed.
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What factors determine protein needs of a person?
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Age, size, metabolic rate, current state of nitrogen balance.
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What are vitamins?
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Potent organic compounds needed in small amounts for growth and good health.
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Which vitamins are water-soluble?
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Vitamins B complex and C.
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What quality does Vitamins A, C and E possess?
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They are antioxidants that disarm tissue-damaging free radicals.
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What is anabolism?
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Reactions where larger molecules or structures built from smaller ones.
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What is catabolism?
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Processes that break down complex structures to simpler ones.
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What happens in oxidation-reduction reactions?
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One substance is oxidized and loses energy by losing electrons, while another substance is reduced and gains energy and electrons transferred from oxidized substance.
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What happens during substrate-level phosphorylation?
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High-energy phosphate groups transfer directly from phosphorylated substrates to ADP.
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What is glycogenesis?
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Formation of glycogen, the animal storage form of glucose, that occurs when excess glucose is ingested.
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What is glycogenolysis?
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Breakdown of glycogen into individual glucose molecules that occurs when blood sugar levels drop.
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What is lipogenesis?
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Reformation of triglycerides from unused glycerol and fatty acid chains for storage in body.
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What is transamination?
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Process of transferring an amine group to alpha-ketoglutaric acid to make glutamic acid.
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Where does oxidative deamination occur?
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In liver.
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When does the absorptive state take place?
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During and shortly after eating when nutrients are moving into the blood from the GI tract.
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What happens to absorbed monosaccharides?
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Delivery to liver and converted into glucose. Used by body cells, stored as glycogen, or converted into stored fats.
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What happens to triglycerides?
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Used for anabolic purposes or stored in adipose (fat) tissue.
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What are sources of blood glucose?
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Glycogen in liver, skeletal muscle cells, adipose tissues, cellular proteins.
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What is glucose sparing?
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Increased use of noncarbohydrate fuel molecules for energy to save glucose during times of fasting.
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What directs all events of the absorptive state?
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Insulin.
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What directs all events of the postabsorptive state?
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Sympathetic nervous system and several hormones.
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Where is cholesterol made?
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In liver and other body cells.
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How is cholesterol removed from the body?
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Through bile salts in feces.
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How is cholesterol transported in the body?
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It binds to small lip-protein complexes called lipoproteins.
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What is energy intake?
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Energy liberated during food oxidation.
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What is energy output?
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Includes energy lost as heat, used to do work, energy stored as fat or glycogen.
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What factors control eating?
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Neural signals from digestive system, bloodborne signals related to body energy stores, hormones, body temp, psychological factors.
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What is the total metabolic rate (TMR)?
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Rate of kilocalorie consumption needed to fuel all ongoing activities both involuntary and voluntary.
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What is conduction?
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Transfer of heat from a warmer object to a cooler one when the two are in direct contact with each other.
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How does convection occur?
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When warm air surrounding body expands and rises and is replaced by cooler air molecules.
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How are heat-promoting mechanisms triggered?
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When external temperature is low; blood temperature falls, heat-romoting center is activated.
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What are some heat-promoting mechanisms?
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Vasoconstriction of cutaneous blood vessels; increased metabolic rate; shivering; enhanced thyroxine release; behavioral modifications.
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What is the purpose of heat-loss mechanisms?
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To protect body from excessively high temps.
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Why are proteins needed?
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For muscle and bone growth.
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What qualities does adipose tissue provide?
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Protective cushion, insulation, energy fuel source.
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What is the role of prostaglandins?
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Smooth muscle contraction, control of bp and inflammation.
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What functions does cholesterol serve?
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Stabilizing component of plasma membranes; precursor from which bile salts, steroid hormones and other essential molecules are formed.
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What is the percentage of fat in the typical American diet?
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40%
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What is the recommended intake of saturated fats?
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10% or less.
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What is the recommended cholesterol intake per day?
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200 mg (1 egg)
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What foods are considered complete proteins?
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Eggs, milk, milk products, meat.
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What foods are considered incomplete proteins?
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Beans, Nuts, seeds, grains, cereals, veggies.
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What is the all or none rule?
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All amino acids needed to make a particular protein must be present in a cell at the same time and in sufficient amounts.
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What must occur in order for optimal protein synthesis to take place?
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Diet must supply sufficient carbohydrate/fat calories for ATP production.
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When is the body in positive nitrogen balance?
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When amount of protein incorporated into tissue is greater than amount being broken down and used for energy.
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When is the body in negative nitrogen balance?
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When protein breakdown for energy exceeds protein amount being incorporated into tissues.
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What do anabolic hormones do?
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Accelerate protein synthesis and growth.
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What is cellular respiration?
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Group of catabolic reactions where food fuels are broken down in cells and some energy released is captured to form ATP.
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What does phosphorylation do?
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Primes molecule to change in a way that increases its activity, produces motion, or does work.
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Describe Stage 1 of Energy-containing nutrient processing.
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Digestion in GI tract. Absored nutrients transported in blood to tissue cells.
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Describe Stage 2 of Energy-containing nutrient processing.
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In cell cytoplasm, nutrients are either built into lipids, proteins glycogen by anabolic pathways or broken down by catabolic pathways to pyruvic acid and acetyl CoA.
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Describe Stage 3 of Energy-containing nutrient processing.
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Almost all catabolic, occurs in mitochondria. Requires oxygen and completes food breakdown, producing CO and water and harvesting large amounts of ATP.
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What are 2 important coenzymes of oxidative pathways?
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NAD+ (niacin), FAD (riboflavin).
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How do cells capture energy liberated during cellular respiration to make ATP?
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Substrate-level phosphorylation and oxidative phosphorlation.
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All food carbohydrates eventually become?
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Glucose.
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Which cells are capable of reversing phosphorylation reactions?
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Intestinal mucosa, kidney tubule, liver cells,
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What are the 3 major phases of the glycolytic pathway?
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Sugar activation and clevage, Oxidation and ATP formation.
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What are the final products of glycolysis?
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2 molecules of pyruvic acid and two molecules of reduced NAD+, with net gain of 2 ATP molecules.
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What is the Krebs Cycle?
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Next stage of glucose oxidation. Occurs in mitochondrial matrix and fueled by pyruvic acid produced during glycolysis.
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Krebs Cycle is aka?
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Citric acid cycle.
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What are the products of the Krebs Cycle?
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2 CO2 molecules, 4 molecules of reduced coenzymes.
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What are purposes of the Krebs Cycle?
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Final common pathway for oxidation of food fuels; source of building materials for anabolic reactions.
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During cellular respiration, what is the energy flow?
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Glucose - NADH + H+ - electron transport chain - proton motive force - ATP.
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What is the percentage of stored fat in the body?
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80 - 85%
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What is the energy source of skeletal muscles that have depleted their energy supply?
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Liver glycogen.
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Define beta oxidation.
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Initial phase of fatty acid oxidation, occuring in mitochondria.
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When does lipogenesis take place?
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When cellular ATP and glucose levels are high.
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What is ketogenesis?
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The conversion of acetyl CoA molecules to ketones by the liver.
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What is metabolic acidosis?
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Body's buffer systems cannot tie up ketones fast enough, and blood pH drops to dangerously low levels.
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What must happen before amino acids can be oxidized for energy?
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They must be deaminated (amine group (NH2) removed).
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Which cells use triglycerides as their primary energy source?
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Adipose, skeletal muscle and liver cells.
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Insulin is classified as what type of hormone?
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Hypoglycemic.
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How does Diabetes Mellitus occur?
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Inadequate insulin production or abnormal insulin receptors.
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What is the primary goal of the postabsorptive state?
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Between meals when blood glucose levels are dropping, to maintain blood glucose levels within homeostatic range (80-100 mg).
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How are triglycerides and cholesterol transported?
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By small lipid protein complexes called lipoproteins.
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What is the role of LDL?
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Transport cholesterol to peripheral tissues, making it available to tissue cells for use later.
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What is the major function of HDLs?
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Transport excess cholesterol from peripheral tissues to the liver.
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What is the consensus on HDLs?
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Good because transported cholesterol is destined for degradation. (Level between 35 - 60 okay)
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What is the consensus on LDLs?
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Bad because when excessive (160 and up), potentially lethal cholesterol deposits are laid down in artery walls.
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What effect does saturated fatty acids have on blood cholesterol levels?
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They stimulate liver synthesis of cholesterol and inhibit its excretion from body.
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What effect does unsaturated fatty acids have on blood cholesterol levels?
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They enhance excretion of cholesterol and its catabolism to bile salts, thereby reducing total cholesterol levels.
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What effect does hydrogenation have on fatty acids?
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It changes fatty acids in the oils to trans fatty acids, which causes serum changes worse than those caused by saturated fats.
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What effect does omega-3 fatty acids have on fats and cholesterol?
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It lowers the proportions of both.
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Between "apples" and "pears", who has the best cholesterol and fat levels?
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Pears.
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What does a cell do when it needs cholesterol?
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It makes receptor proteins for LDL and inserts them in its plasma membrane.
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What is Body Mass Index?
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Official medical measure of obesity and body fatness.
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What are orexins?
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Peptide that enhances appetite.
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What is Neuropeptide Y?
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Peptide in hypothalamus that causes carbohydrate craving (most potent appetite stimulant known).
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What is Galanin?
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Peptide causing craving for fats.
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What does GLP-1 and serotonin do?
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Make us feel full and satisfied (receptors in hypothalamus).
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What are some other hormonal controls (besides Insulin) that affect appetite?
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Epinephrine (released during fasting) triggers hunger.
Cholecystokinin depresses hunger. |
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What is Leptin?
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Satiety signal secreted by fat tissue in response to increase in body fat mass.
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What is throxine?
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"Metabolic hormone" that directs body cells to increase O2 consumption, by accelerating use of ATP to operate sodium-potassium pump.
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What is Total Metabolic Rate (TMR)?
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Rate of kilocalorie consumption needed to fule all ongoing activities involuntary and voluntary.
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What is the normal body temperature average and range?
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36.2C (98.2F) average
35.6 - 37.8C (96-100F) range |
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Where is the best indicator of core temperature on the body?
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The rectum.
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What is insensible water loss?
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Basal level of body heat loss due to continuous evaporation of water from lungs, oral mucosa and skin.
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What is insensible heat loss?
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The heat loss that accompanies insensible water loss.
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What is the main integrating center for thermoregulation?
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The Hypothalamus.
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Define Chemical (nonshivering) thermogenesis.
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The release of norepinephrine by sympathetic nerve fibers in response to cold that elevates metabolic rate.
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Define Shivering.
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Brain centers controlling muscle tone activate when cold; when muscle tone reaches sufficient levels to alternately stimulate stretch receptors in muscles, muscles begin involuntary shuddering contractions.
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Define Phenylketonuria (PKU).
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Tissue cells are unable to use amino acid phenylalanine, that is present in all protein foods. Causes brain damage and retardation.
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Define Galactosemia.
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Lack of liver enzymes needed to transform galactose to glucose. Leads to mental deficits.
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Define Kwashiorkor.
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Severe protein deficiency in children, resulting in mental retardation and failure to grow.
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