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Nutrition Definitions & Concepts. Created by: Howard Tyler, PhD Modified by: Chelsea A. Iennarella. Nutrition. series of digestive and metabolic processes in which feed is consumed and absorbed into the body for the purposes of maintenance, growth, repair, work, etc.
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Nutrition Definitions & Concepts Created by: Howard Tyler, PhD Modified by: Chelsea A. Iennarella
Nutrition • series of digestive and metabolic processes in which feed is consumed and absorbed into the body for the purposes of maintenance, growth, repair, work, etc. • nutrition integrates chemistry, biochemistry, physiology, and genetics
Nutrition Involves Processes Of: • ingestion: apprehension of feed, chewing, and swallowing to the initial digestive organs • digestion: reduction of food to utilizable form; physical and chemical processing of ingested food • absorption: active transport and passive diffusion • metabolism: the chemical breakdown and synthesis of molecules needed to maintain the life of a living thing
Need for Nourishment • Wild animals eat a variety of foods to obtain proper nutrients • Domesticated animals or wild animals in captivity depend on humans to provide a balanced ration • 3 Things Nutritionists Need to Understand: • animals nutrient requirements or needs • the nutrients provided by different feeds and combinations of feeds • the ability of the animal to ingest, digest, and metabolize different feeds
Feed • food, as it is fed to livestock or other animals • examples • corn silage • hay • soybean meal (SBM) • wheat
Substrate • the material or substance on which an enzyme acts • examples • amino acid • monosaccharide • fatty acid • does NOT end in –ase • -aseindicates an enzyme not a substrate
Nutrient • a substance that an organism must obtain from its surroundings for growth and the sustenance of life • used to obtain energy, synthesize tissues, or regulate body processes Which nutrients provide energy to the body?
Essential vs. Nonessential Nutrients • essential nutrient: a substance that must be obtained in the diet, because the body either cannot make it or cannot make adequate amounts of it • nonessential nutrient: one that the body can make sufficient quantities of it if it is lacking in the diet
Macronutrients vs. Micronutrients • macronutrient: a nutrient that is needed in relatively large amounts in the diet • protein • carbohydrates • lipids • water • micronutrient: a nutrient that is needed in relatively small amounts in the diet • vitamins • minerals
Major Functions of Nutrients • synthesis of tissue constituents • energy • cofactors for metabolic reactions • Regulation of body functions
Synthesis of Tissue Constituents • protein • muscle and enzymes • nucleic acids • DNA, RNA • bone • Ca, P
Energy • Sources of energy and their respective (heat of combustion) • carbohydrates (4 kcal/g) • lipids (9 kcal/g) • protein (5 kcal/g; what energy is provided to tissues is discounted to 4 kcal/g due to urea synthesis) • Used for • maintenance • tissue growth • storage
Cofactors for Metabolic Reactions • Vitamins • B vitamins for energy metabolism • Minerals • Ca2+ • Mg2+
Regulation of Body Functions • Hormones • Protein (insulin) • Steroid (estrogen, testosterone) • Prostaglandin (PGE, PGF2α) • Neurotransmitters
Catabolism vs. Anabolism • catabolism:is the metabolic breakdown of complex molecules into simpler ones, often resulting in a release of energy • anabolism: is constructive metabolism concerned especially with macromolecular synthesis
Metabolism • the total of the chemical reactions that maintain the life of a living thing catabolism + anabolism = metabolism
Glycolysis • the process in cell metabolism by which carbohydrates and sugars, especially glucose, are broken down, producing ATP, NADH, and pyruvate
Glycogenesis • the formation of glycogen from monosaccharides in the body esp. glucose • glycogen a highly branched group of chemically linked glucose molecules GLYCOGEN MOLECULE
Glycogenolysis • the biochemical breakdown of glycogen to glucose • taken from stores to use as energy • catabolizes by cleaving off glucose molecules • glycogen stores depleted within 24 hours of human fasting
Gluconeogenesis • the formation of glucose from non-carbohydrate sources, such as amino acids, propionate, or lactate • does NOT occur from fatty acids • NOT simply a reversal of glycolysis What species rely more heavily on gluconeogenesis for the production of glucose?
Helpful Hints for Tests & Quizzes • when asked to list from least to greatest, label each end as such LEAST MOST • spell correctly, many words are spelled similarly and you must be clear • when asked for digestive functions, think of enzymes and food breakdown • when asked for absorptive functions, think of transport processes