MCAT Biology

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  1. 5' cap
    a methylated guanine nucleotide added to the 5' end of eukaryotic mRNA. The cap is necessary to initiate translation of the mRNA.
  2. "A" band
    the band of the sarcomere that extends the full length of the think filament.
  3. Absolute refractory period
    a period of time following an action potential during which no additional action potential can be evoked regardless of the level of stimulation
  4. Accessory glands
    • the 3 glands of the male reproductive system that produce semen:
    • seminal vesicles, prostate, and bulbourethral glands
  5. GI accessory organs
    liver, gallbladder, pancreas, salivary glands
  6. acetyl-CoA
    the first substrate in the Krebs cycle, produced primarily from the oxidation of pyruvate by the pyruvate dehydrogenase complex.
  7. acinar cells
    cells that make up exocrine glands, and that secrete their products into ducts
  8. acrosome
    a region at the head of a sperm cell that contains digestive enzymes which, when released during the acrosome reaction, can facilitate penetration of the corona radiata of the oocyte and fertilization
  9. actin
    a contractile protein. In skeletal and cardiac muscle, it polymerizes to form the thin filaments
  10. adenine
    On of the four aromatic bases found in DNA and RNA. It is a purine and pairs with thymine (DNA) and uracil (RNA)
  11. adrenal medulla
    releases epinephrine and norepinephrine
  12. afferent artiole
    the small artery that carries blood toward the capillaries of the glomerulus
  13. albumin
    produced by the liver to help maintain blood osmotic pressure
  14. amino acid acceptor site
    the 3' end of a tRNA molecule that binds an amino acid
  15. aminoacyl tRNA
    a tRNA with an amino acid attached; made by an aminoacyl-tRNA synthetase
  16. amylase
    an enzyme that digests starch into disaccharides. Secreted by salivary glands and pancreas
  17. androgens
    male sex hormones
  18. antidiuretic hormone
    aka "vasopressin", is produced by the hypothalamus and secreted by the posterior pituitary. Targets the kidney tubules to increase their permeability to water and thus increase water retention
  19. the A-site
    Aminoacyl-tRNA site; the site on a ribosome where a new amino acid is added to a growing peptide
  20. auxotroph
    a bacterium that cannot survive on minimal medium(glucose alone), because they cannot synthesize a molecule needed to live
  21. bacillus
    rod-like shaped bacteria
  22. Blotting
    the transfer of DNA or proteins from an electrophoresis gel to a nitrocellulose filter
  23. Bohr effect
    the tendency of certain factors to stabilize hemoglobin in the tense conformation, thus reducing its affinity for oxygen and enhancing the release of oxygen to the tissues
  24. Bowman's capsule
    the region of the nephron that surrounds the glomerulus. It collects the plasma that is filtered from the capillaries in the glomerulus.
  25. calmodulin
    A cytoplasmic Ca2+ binding protein, important in smooth muscle cells
  26. capsid
    outer protein coat of a virus
  27. carbonic anhydrase
    an enzyme in eruthrocytes that catalyzes the conversion of CO2 and H2O into carbonic acid
  28. chief cells
    pepsinogen-secreting cells found at the bottom of the gastric glands of the stomach
  29. cholecystokinin
    a hormone secreted by the small intestine in response to the presence of fats. It promotes the release of bile from the gallbladder and pancreatic juices from the pancreas
  30. coccus
    a round shaped bacteria
  31. co-factor
    an inorganic molecule that associates non-covalently with an enzyme, and that is required for the proper functioning of the enzyme
  32. cooperativity
    a type of substrate binding to a multi-active site enzyme, in which the binding of one substrate molecule facilitates the binding of subsequent substrate molecules
  33. desmosome
    a general cell junction, used primarily for adhesion
  34. DNA polymerase
    the enzyme that replicates DNA. Eukaryotes have a single version and Prokayotes have 3
  35. ectoderm
    ultimately forms external structures such as skin, hair, nails, inner lining of mouth and anus, and the nervous sytem
  36. efferent arteriole
    the small artery that carries blood away from the capillaries of the glomerulus
  37. ELISA
    a biochemical technique that utilizes antigen-antibody interactions to determine the presence of either antigens of specific immunoglobulins in a sample
  38. endoderm
    ultimately forms internal structures, such as the inner lining of the GI tract and some glandular organs
  39. enterogastrone
    a hormone secreted by the small intestine in response to the presence of food.
  40. enterokinase
    a duodenal enzyme that activates trypsinogen to trypsin
  41. epitope
    the specific site on an antigenic molecule that binds to a T-cell receptor or to an antibody
  42. euchromatic
    DNA that is loosely packed around histones. DNA is more accessible to enzymes and can be activated if needed
  43. facultative anaerobe
    an organism that will use oxygen to produce energy if it is available, and that can ferment if it is not
  44. fibrinogen
    a blood protein essential to blood clotting
  45. gastrin
    a hormone released by the G cells of the stomach in the presence of food. Promotes muscular activity of the stomach as well as secretion of hydrochloric acid, pepsinogen, and mucus
  46. DNA gyrase
    a prokaryotic enzyme used to twist the single circular chromosome of prokaryotes upon itself to form supercoils.
  47. Human chorionic gonadotropin
    a hormone secreted by the trophoblast cells of a blastocyst that prolongs the life of the corpus luteum, and thus increases the duration and amount of progesterone. This helps to maintain the uterine lining.
  48. helicase
    enzyme that unwinds the double helix of DNA and separates the DNA strands in preparation of replication
  49. hexokinase
    enzyme that catalyzes the phosphorylation of glucose to form glucose-6-phosphate in the first step of glycolysis
  50. histones
    globular proteins that assist in DNA packaging in eukaryotes
  51. H zone
    the region at the center of an A band of a sarcomere that is made up of myosin only. Gets shorter with muscle contraction
  52. I band
    the region of a sarcomere made up only of the thin filaments. Alternate with A bands to give striation
  53. interleukin
    a chemical secreted by a T cell that stimulates activation and proliferation of other immune system cells
  54. kinase
    an enzyme that transfers a phosphoryl group from ATP to other compounds
  55. Kmm
    The substrate concentration required to reach 1/2 Vmax
  56. Krebs cycle
    acetyl-CoA is combined with oxaloacetate to form citric acid. The citric acid is then decarboxylated twice and isomerized to recreate oxaloacetate
  57. Law of segregation
    states that two alleles of a given gene will be separated from one another during gamete formation
  58. ligase
    an enzyme that connects two fragments of DNA to make a single fragment. Used during DNA replication
  59. lysozyme
    an enzyme that lyses bacteria by creating holes in their cell walls
  60. macula densa
    the cells of the distal tubule at the juxtaglomerular apparatus
  61. mesoderm
    ultimately forms "middle" structures such as bones, muscles, blood vessels, heart, kidneys,....
  62. Okazaki fragments
    small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand
  63. phosphatase
    an enzyme that removes a phosphoryl group from a compound
  64. phosphofructokinase
    enzyme used in third step of glycolysis (main regulatory step). PFK is feeback-inhibited by ATP
  65. proximal convoluted tubule
    site of most reabsorption in nephron; all filtered nutrients as well as most filtered water is reabsorbed here
  66. P-site
    • peptidyl-tRNA site;
    • site of a ribosome where the growing peptide is found during translation
  67. renin
    enzyme secreted by juxtaglomerular cells when BP decreases; Renin converts angiotensinogen to angiotensin I
  68. respiratory alkalosis
    a rise in blod pH due to hyperventilation and a resulting decrease in CO2
  69. saprophyte
    an organism that feeds of dead plants and animals
  70. secretin
    hormone secreted by the small intestine in response to low pH. Promotes the release of bicarbonate from the pancreas to act as a buffer
  71. S phase
    phase of cell cycle during which the genome is replicated
  72. spirochete
    spiral shaped bacteria
  73. topoisomerase
    enzyme that cuts one or both strands of DNA to relieve the excess tension caused by the unwinding of the helix by helicase during replication
  74. Z lines
    the ends of a sarcomere
  75. autotroph
    uses CO2 as carbon source
  76. What structure must all viruses have?
  77. what triggers relaxation of bronchiol smooth muscle
    the activation of the sympathetic nervous system
  78. what type of gland is the liver
    exocrine gland
  79. what is pulse pressure?
    difference between systolic and diastolic BP
  80. what is lactose intolerance due to?
    due to the decrease in the level of expression of β-galactosidase
  81. calcitonin
    secreted in response to high serum Ca2+; it inhibits osteoclast-mediated bone breakdown and increases osteoblast-mediated bone formation
  82. parathyroid and calcitriol
    both increase bone reabsorption and decrease bone formation
  83. where is red marrow?
    spongy bone of flat bones
  84. role of surfactant
    to reduce surface tension
  85. when does secondary oocyte become ootid?
    after fertilization, before egg and sperm nuclear membranes fuse
  86. Southern blotting
    allows you to detect the presence of specific sequences within a heterogeneous sample of DNA. Also allows you to isolate and purify target sequences of DNA
  87. Northern blotting
    same as southern blotting, except that mRNAs are separated via gel electrophoresis instead of DNA
  88. Western blotting
    allows you to detect the presence of certain proteins with a sample and also serves as a diagnostic tool
Card Set:
MCAT Biology
2014-07-27 22:17:51

MCAT biology
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