Meat Science

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Meat Science
2012-02-27 17:13:20
muscle composition

Exam 1
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  1. Three types of muscle
    • Smooth - involuntary
    • Striated - Involuntary
    • Striated - voluntary
  2. Muscle that makes up arteries, veins, GI tract
    Smooth involuntary
  3. Muscle making up cardiac muscle
    Striated involuntary
  4. Skeletal muscle
    striated voluntary
  5. true cell of the muscle
    muscle fiber
  6. muscle bundles contain _____ which contain ______
    fibers, microfilaments
  7. membrance surrounding the muscle fiber
  8. sarcolemma is composed of
    proteins and lipids
  9. Tubules that form around the circumference of the sarcolemma are called
    transverse tubules (t-tubules)
  10. Motor nerve fibers terminate on the sarcolemma at the
    myoneural junction
  11. raised structures at the myoneural junction are called the
    motor end plates
  12. cytoplasm of muscle cells is called
  13. the sarcoplasm is composed of
    75 - 80% water, lipids, glycogen, ribosomes, proteins, non-protein nitrogenous compounds, and inorganic constituents
  14. Located at the periphery of the fiber and beneath the sarcolemma
    Number not consistent
  15. Myofibrils compare to
    organelles of a regular cell
  16. extend entire length of fiber, composed of myofilaments
  17. composed of thick and thin filaments
  18. This gives muscle its striated appearance
    where thick and thin filaments overlap forming dark bands
  19. Proteins in a muscle cell
    • Actin
    • Myosin
    • Tropomyosin
    • Tropin
    • nebulin
    • titin
  20. Actin is (thick/thin)
  21. Myosin is (thick/thin)
  22. actin to myosin ratio
  23. Light band is called the
    I band
  24. Dark band is called the
    A band
  25. The I band is bisected by a thin dark band called
    the Z disk (line)
  26. The unit of the myofibril between 2 Z disks is
    a sarcomere
  27. Saromere contains ___ A band(s) and _____ I band(s)
    1, two 1/2
  28. ____ and ____ are constant
    M line and A band
  29. ____ filaments make up the A band
  30. ____ filaments make up the I band
  31. 6 ___ filaments surround 1 ____ filament
    actin, myosin
  32. There are only ____ filaments in the H zone
  33. There are only ____ filaments in the I band
  34. Actin filaments attach at the
    z disk
  35. ____z filaments attach to one actin filament
  36. actin and myosin are classified as
  37. troponin and tropomyosin are classified as
    regulatory proteins
  38. titin and nebulin are classified as
    cytoskeletal proteins
  39. Actin is composed of _____ and ______ proteins
    Globular and Fibrous
  40. _______ polymerize to make a helix which is called ________
    G-actin, F-actin
  41. Tropomyosin has sub units of
  42. Actin is ___% of myofibrillar protein
  43. Myosin is ___% of myofibrillar protein
  44. myosin is ____ shaped
  45. area that contains the rod portion only and no bands is called
    the pseudo H zone
  46. This protein functions as a molecular spring and is responsible for passive elasticity. It connects the Z line to the M line
  47. actin-binding protein which is localized to the I band
  48. Membranous system of tubules and cisternae
    Sarcoplasmic Reticulum
  49. site of calcium storage
  50. run parallel to the myofibril
  51. L-tubules converge in the H zone to form the
    fenestrated collar
  52. L-tubules converge at the A & I band junction with transversely oriented tubular elements called
    terminal cisternae
  53. Most abundant protein in the body
    connective tissue
  54. _____ tissue has a limited number of extracellular fibers
  55. CT surrounding muscles is known as
    connective tissue proper
  56. CT associated with bones and cartilage is known as
    supportive CT
  57. harnesses energy of the muscle
    connective tissue
  58. influences meat tenderness
  59. principal structural component of CT
  60. most abundant amino acid in collagen
  61. _____ amount is consistent and unique to collagen
  62. Insolubility and strength of collagen is the result of
    intermolecular cross linkages
  63. A mature carcass has more
    cross linkages
  64. enlargement of existing cells is called
  65. multiplication or production of new cells is called
  66. process by which cells and organs acquire individual characteristics
  67. organization of dividing cells into specific organs
  68. It is hard to determine when maturation occurs because
    because tissues and body parts grow and develop at different rates
  69. when organs begin to degenerate without complete repair or replacement
  70. Ovum phase lasts up to ___ days
  71. tissue, organs, and systems are differentiated in the
    Embryonic phase
  72. embryonic phase lasts
    25 to 45 days
  73. myogenic cells undergo mitosis to form
  74. myoblasts fuse and donate nuclei to a single immature muscle fiber known as
    a myotube
  75. Hyperplasia occurs during the first ____ of prenatal period, and hypertrophy occurs during the last ____
    2/3, 1/3
  76. proliferation of myfibrils occurs through
    longitudinal splitting of large myofibrils into 2 daughter cells
  77. growth in length occurs by
    addition of sarcomeres
  78. new nuclei are created by
    satellite cells
  79. satellite cells provide fibers with added ____ which increases muscle's ability to synthesize protein and grown
  80. BCTRC
    boneless closely trimmed retail cuts
  81. larger diameter fibers are called
    white fibers
  82. Currently there are ___ growth promotants on market in US
  83. Somatotropin is produced by the
    anterior pituitary
  84. Somatotropin responsible for ____ tissue growth
  85. Somatotropin promotes the release of ____ from the liver
  86. HGH is produced by
    recombinant DNA technology
  87. rBST is known as
    recombinant bovine somatotropin
  88. rBST was developed by Monsanto and called
  89. Posilac is used to increase
    milk production
  90. Epinephrine and norepinepherine are from the
    adrenal medulla
  91. epinephrine and norepinephrine activate tissue receptors called
    beta - receptors
  92. Testes produce
  93. some synthetic estrogens are:
    • estradiol 17-beta
    • zeronol
    • estradiol benzoate
  94. a synthetic androgen is
    trenbolone acetate
  95. synthetic androgens increase
    feed efficiency and carcass leanness
  96. Hormone like substances with chemical structures similar to epinephrine and norepinephrine are called
    beta adrenergic agonists
  97. ______ shift nutrient utilization away form fat deposition toward muscle accretion
    beta agonists
  98. Paylean, Optaflex, Zilmax
    beta agonists
  99. Use of hormones averages ___% improvement in rate of gain, and ___% improvement in feed efficiency
    10, 6-8
  100. hormone fed to heifers to supress estrus
    MGA (melengestrol acetate)
  101. hormone approved in the 50's and then found to cause cancer
  102. initial homeostatic control mechanisms that result from exsanguination
    loss in blood pressure causes increased heart rate and constriction of blood vessels which forces blood to vital organs
  103. Why is blood removal necessary
    it is an excellent medium for bacterial growth
  104. What happens to the pH post mortem
    • aerobic metabolism fails which causes metabolism to switch to the anaerobic pathway.
    • Lactic acid accumulates until stored glycogen is depleted
  105. How do you prevent rapid denaturation of proteins as pH decreases
    Chill the carcass
  106. _______ is required for muscle to remain in a relaxed state
    ATP Mg2+
  107. Why is rigor postponed?
    Creatine phosphate is stored postmortem and used to convert ADP back to ATP
  108. What causes rigor
    creatine phosphate and glycogen stores are used up and ATP becomes limiting. Actomyosin bridges are formed and these bonds cannot be broken without ATP
  109. Decreased tension after rigor is due to
    proteolytic degradation of specific myofibrillar proteins
  110. Rigor involves 100% of binding sites, unlike normal contraction which involves ___%
  111. ______ and ______ are closely correlated because both involve energy metabolism
    Rigor mortis and pH decline
  112. Steps of protein degradation during aging
    • Degradation of the Z disks
    • As z disk degrade, tension from rigor causes myofibrils to rupture at the z disk/I band junction
    • Calcium released post mortem activates the calpain system
  113. Proteins which undergo degradation during aging
    • desmin
    • troponin - T
    • titin
    • nebulin
  114. ______ inhibits calpain activitiy
  115. First meat packer
    William Pynchon - salted pigs
  116. first meat scientist
    Benjamin Franklin
  117. first meat packing plant
    cincinnati - porkopolis