Card Set Information

2013-11-21 19:46:40

This set of cards will go into details of the metabolism and energy in the body (and some information on animals)
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  1. What is Energy?
    The capacity to do work
  2. What is energy metabolism?
    All of the chemical exchanges that occur in a living animal or cell
  3. Where does Energy metabolism originate from?
    Chemical energy of food
  4. What are the two types of energy metabolism?
    Anabolism and Catabolism
  5. What happens during anabolism?
    Small, simple precursors are built into larger and more complex molecules, including lipids, polysaccharides, proteins and nucleic acids
  6. What is required for anabolism to occur?
    The input of energy (generally in the forms of free energy of hydrolysis of ATP and the reducing power of NADH and NADPH.
  7. What is catabolism?
    Degradative phase of metabolism, in which organic nutrient molecules (carbs, fats, and proteins) are converted into smaller, simpler end products (ex. Lactic acid, CO2, H2O, NH3)
  8. What happens during the catabolic pathway?
    release of free energy, some of which is conserved in the formation of ATP and reduced electron carriers (NADH, NADPH)
  9. What is ATP?
    And what does it do?
    Adenosine Triphosphate

    Carries chemical energy between metabolic pathways by serving as a shared intermediate coupling endergonic and exergonic reactions.
  10. What is NAD+?
    Nicotinamide adenine dinucleotide
  11. NADP
    Nicotinamide adenine dinucleotide phosphate

    Co-enzymes functioning as carriers of hydrogen atoms and electrons in some oxidation-reduction reactions (contains niacin, a B- vitamin)
  12. FAD
    Flavin adenine dinucleotide

    Co-enzymeof some oxidation-reduction enzymes (contains riboflavin)
  13. What is energy balance?
    Amount of nutrient consumed is sufficient to maintain a constant body weight
  14. What are the three forms of energy?
    • -Chemical (photosynthesis)
    • -Mechanical (Muscle movement)
    • -Electrical (migration of ions across cell membranes)
  15. What are the two types of Autotrophs?
    Phototrophs and Lithotrophs
  16. What are the sources of energy?
    Autotrophs and heterotrophs
  17. What are phototrophs?
    • Use light for energy
    • (photosynthetic bacteria and higher plants)
  18. What are lithotrophs?
    Use chemical energy (chemoautotrophs)

    Oxidize inorganic compounds (H2S, S, NH4+, Fe2+
  19. What are the two two types of heterotrophs?
    Photoheterotrophs and chemoheterotrophs.
  20. What are heterotrophs?
    organisms that cannot use atmospheric COand must obtain carbon from their environment in the form of complex organic molecules
  21. What are photoheterotrophs?
    Produce ATP from light and use organic compounds to build structures (ex. purple bacteria and green bacteria)
  22. What are Chemoheterotrophs?
    Produce ATP by oxidizing chemical substances (CHO, Protein, and fat)
  23. Is energy required in larger or smaller amounts than any other nutrient?
    Larger! (Animals eat to fill energy requirements and they love fat, body stores it.)
  24. What is most often the limiting factor in livestock production?
  25. Energy is the major _______ associated with feeding animals.
    Cost (apprx. 24% of cost of production)
  26. Animal ____________ at transforming _____ into it's own body energy.
    not efficient

    Feed energy
  27. What are the three methods of measuring energy value of feedstuffs?
    • Total Digestible Energy (TDN)
    • Starch equivalent (SE)
    • Caloric System (partitioning energy)
  28. %TDN = ?
    [{(digestible (protein+fiber+Nitrogen-free-extract +(fat x 2.25)}/ (feed consumed)] X 100
  29. How much more energy does fat contain than carbs?
  30. What are the steps in determining the TDN value?
    • -digestibility
    • -computation of digestible nutrients
    • -computation of total digestible nutrients (TDN) --> %TDN= %DCP +% DCF + DNFE + (%DEE x 2.25)
  31. How is TDN usually expressed?
    as a percent of the ration or in units of weight (kg or lb)
  32. What is Nitrogen-Free-Extract?
    • NFE
    • -soluble carbs of feed such as sugar and starch
    • (%NFE=%DM-(%EEfor fat +%CP +%ash +%CF)
  33. Why is Nitrogen-Free-Extract a bad name for what it actually is?
    • -fraction has nothing to do with nitrogen
    • -it is not an extract
    • - not determined by chemical analysis but by differences
    • -accumulates all the errors that exist in proximate analysis
  34. How digestible is protein?
  35. What is the advantage of using Total digestible nutrients (TDN) system?
    Used for a long time and many people are acquainted with the system.
  36. What are the disadvantages of using TDN system
    • - misnomer (not actual total of digestible nutrients in feed- does not include digestible mineral matter, also since digestible fat is multiplied by a factor of 2.25' feeds high in fat could have TDN values exceeding 100%
    • -TDN is based upon chemical determinations and not related to actual metabolism of the animal
    • -expressed as a percent or in weight whereas  energy is expressed in calories
    • -Consider only digestive losses; does not take into account losses in the urine, gases and increased heat production
    • -over-evaluates roughages in relation to concentrates due to heat loss in high fiber feeds
  37. What is the starch equivalent?
    Expressed energy values of feeds relative to the net energy value of the common feed constituent, starch. (to find just divide by starch value (4?) from whatever is being compared)
  38. What are the units of energy?
    Calories. 1 Calorie=4,184 joules. 1000 calories=1C=1 kcal
  39. What is a Calorie?
    A unit of heat used to describe the energy-yeilding capability of foods (and fuels) on complete combustion.  

    It's also the amount of heat required to raise 1 gm of pure water from 14.5 to 15.5 degrees
  40. What is involved in energy partitioning?
    • Gross energy
    • Digestible energy
    • Metabolizable energy
    • Net energy (NEm, NEp)
  41. What is gross energy? (GE)
    Total energy in feed. 

    Heat generated when a unit mass of feed is completely combusted in oxygen to yield water and CO2 under std Temp and pressure. (25-30 atmospheres of oxygen)

    All the energy not available to the animal*
  42. What is used to determine the gross energy?
    Bomb calorimeter
  43. What is Digestible energy (DE)?
    Gross Energy - feces [(GE of Feed per unit dry wt.X dry wt. of feed) - (GE of feces per unit dry wt. X dry wt. of feces)
  44. So what is the fecal energy?
    • Energy of undigested dietary nutrients
    • Energy of endogenous secretions (secretion left in feces, mucus)
  45. What is DE a main calculation for?
    And what species do not use it at all?

  46. What is Metabolizable Energy (ME)?
    Digestible Energy - Energy of urine, and gaseous products.
  47. What is the urinary energy percentage of GE in non-ruminants?
    2-5% GE
  48. What is the urinary energy percentage of GE in ruminants?
    4-6% GE
  49. What is the gaseous energy percentage of GE in non ruminants?
    0-2% GE
  50. What is the gaseous energy percentage of GE in ruminants?
    6-10% GE
  51. What animal is ME the most common method used in?
  52. Does water affect energy measurements?
  53. What is Net Energy (NE)?
    • Useful energy
    • - the difference between metabolizable and the heat increment and includes the amount of energy used for maintenance only (NEm) or maintenance plus production (NEp)
    • NE= ME -HI
  54. Is NE very accurate?

    Is it easy to determine?
    Yes, very accurate measure of energy value of feed

    No, hard to determine
  55. What is the Heat Increment of Feed?
    • composed of heat released through body.
    • - ingestion digestion and metabolism of nutrients derived
    • - Act of eating (energy cost about 3-6% ME intake) [chewing, swallowing, metabolism of gut microflora in ruminants (7-8% ME intake), secretion of saliva]
  56. Is corn or alfalfa a more efficient source of energy?
    Corn (alfalfa has more fiber, decreasing digestibility and making it less efficient)
  57. Is true digestibility easy or hard to measure in poultry?
    • Hard
    • because undigested residues and urinary wastes are excreted together.
    • (so it's easier to use ME of diet by pooling excreta as a single material representing unutilized portion of the feed energy
  58. What is used to measure energy in Pigs?
    • DE is preferred system
    • - easy to measure
    • -gaseous products from pigs considered to e insignificant (<0.006 GE intake) and are ignored
  59. What is the energy partition scheme in ruminants (energy used to measure)
    • - ME system (considers gas lost (methane production)
    • -NE system (animal requirements stated as net energy are independent of the diet, and feed requirements for maintenance are separate from feed needed for productive functions)
  60. are larger or smaller animals more energy efficient?
    Smaller animals, have less to work with.
  61. what are major contributors to heat production in an animal receiving a maintenance supply of dietary energy (in regards to diet)
    • -work done in location, prehension and mastication of feed
    • -work done by movement of digestive tract
    • -heat and fermentation of certain dietary constituents
    • -Heat increment  associated with the metabolic processing of nutrients
  62. what are major contributors to heat production in an animal receiving a maintenance supply of dietary energy (in regards to non-food activities)?
    • -maintaing body temp
    • -work of circulation, respiration, maintenance of posture, standing and locomotion
    • -energy cost of basic metabolic processes including tissue turnover