BMB 401

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BMB 401
2014-04-02 01:20:02

test 3 baby!!!!!!
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  1. choose the correct statement:
    a: an example of a nucleoside is adenine joined via an N-glycosidic bond to D-ribose
    b: the phosphate covalently linked to the 5'-carbon of D-ribose in ATP is called the gamma phosphate
    c: uracil and adenine are pyrimidines
    d: at pH 7, guanine isomerizes to hypoxanthine by keto-enol tautomerism
    a. nucleosides are nitrogenous bases linked to the 1'carbon via a glycosidic bond to D-ribose
  2. what is true about this figure?
    a: this molecule is dADP
    b: relative to the pentose sugar, the nitrogenous base is in the syn conformation
    c: this molecule is ADP
    d: this molecule is GDP
    d:  the molecule on the 1' carbon is guanine
  3. choose the correct statement:
    a: given two duplex DNAs of 100 base pairs, an increase in temps will cause a DNA that has more AT-base pairs to denature more readily than a DNA that has less AT-base pairs
    b: in single stranded DNA, each deoxyribose molecule is joined to the nitrogenous base of the neighboring nucleotide by a phosphodiesterase bond
    c: a duplex nucleic acid in the "A form" always contains more purines than pyrimidines
    d: the major groove in B form DNA is due to supercoiling
    a: GC-base pairs are more stable than AT-base pairs due to more hydrogen bonds.
  4. true or false. at equal concentrations, duplex DNA will absorb less UV light than will single stranded DNA.
  5. true or false. in bacteria the ribosome is composed of a small unit that is 30s in size and a small subunit that is 60s in size.
    false bacteria have 30S and 50S
  6. true or false. in eukaryotes, a primary transcript (also called hnRNA) containing three exons encodes three unique peptides
    false the exons are fused together by removing interons and code for one protein
  7. true or false. the eukaryotic ribosome contains only one ribosomal RNA each for the small and large subunits. these ribosomal RNAs contain modified nucleotides
  8. choose the correct statement:
    a: uracil transiently exists in DNA by spontaneous deamination of thyamine. fortunately, repair enzymes recognize and then replace the uracil with thymine
    b: under alkaline conditions, a single event of hydrolysis of RNA produces new ends with 5' phosphate and a 3'-OH
    c: the B form of DNA is stabilized with hydrogen bonding and base pair stacking interactions
    d: treatment of DNA with ethidium bromide leads to the loss of purines in DNA
    c: this is true
  9. choose the correct statement:
    a: the A form of duplex nucleic acid is longer and thinner than B form DNA
    b: the B form of duplex DNA has 10 base pairs per turn in which each base of a base pair is not exactly perpendicular to the long axis of the helix, but is tilted. this slight tilt is called propeller twist.
    c: single stranded DNA is very flexable because the pentose sugar lacks a hydroxyl group at the 2'position
    d: a segment of GC base pairs in the Z DNA conformation is a right-handed helix
    b: true answer
  10. choose the appropriate response. for a circular duplex DNA that has 400 base pairs, if Tk=43 and Wk=-3:
    a: delta-L=+6, so this DNA is positively supercoiled
    b: delta-L=-6, so this DNA is negatively supercoiled
    c:delta-L=0, so this DNA is relaxed
    d: this DNA must carry a cruciform structure
    c: is correct T is +3 and W is -3 so delta-L is 0
  11. name all the pyrimidines.
    cytosine, uracil, and thymine
  12. name all the purines.
    adenine and guanine
  13. what distinguishes cytosine?
    NH2 group on the top with an O group ortho oriented
  14. what distinguishes uracil?
    oxygen group on top and oxygen group ortho and hydrogen group para
  15. what distinguishes thymine?
    oxygen group on top and oxygen group ortho and hydrogen group para with CH3 group para opposite ortho oxygen group
  16. what distinguishes guanine from adenine?
    guanine has three groups while adenine has only one.
  17. what is different about the keto and enol forms?
    keto forms are oxidized with one double bond on the ring interior, while enol forms are r=fully reduced with three double bonds around the ring.
  18. what are pyrimidines?
    six member aromatic rings
  19. what are purines?
    fused five and six member rings
  20. what is polysystronic mRNA?
    its is RNA that codes for multiple genes and allows for coexpression
  21. for bacteria 30S and 50S equal what total unit?
    70S ribosome
  22. for eukaryotic ribosomes, 40S and 60S make what unit for ribosomes?
    80S total ribosome
  23. gluconeogenesis is the synthesis of:
    glucose from non carbohydrate precursors
  24. the pentose phosphate pathway is an important source of _____, and for ______, an essential precursor for ATP, NAD+, FAD, CoA, DNA, and RNA
    NADPH, ribose-5-phosphate
  25. out of these five things, which is not a substrate for gluconeogenesis?
    a: glycerol
    b: lactate
    c: acetate
    d: pyruvate
    e:most amino acids
    c: acetate
  26. the major tissues carrying out gluconeogenesis are the ____ and _____
    liver, kidneys
  27. glucose monitoring devices use the reaction, glucose+O2+H2O--> gluconate+2_______, which is catalyzed by the enzyme ________
    H2O2; gluconate synthase
  28. in the gluconeogenic pathway, the three regulated reactions of glycolysis catalyzed by _______,_____, and _____ are replaced by alternative reactions
    glucokinase, phosphofructokinase, pyruvate kinase.
  29. all of the following enzymes are unique to gluconeogenesis except...:
    a: phoshpoglucoisomerase
    b: glucose-6- phosphate
    c: pyruvate carboxylase
    d: fructose-1,6-bisphosphatase
    e: PEP carboxykinase
    a: phosphoglucoisomerase
  30. what four things are required for pyruvate carboxylase?
    biotin covalently linked to enzyme, ATP, acetyl-CoA as an allosteric activator, and tetrameric enzyme in the mitochondria
  31. what is the cori cycle?
    the cori cycle is the lactic acid cycle during anaerobic conditions.
  32. why is glucose important in the body?
    glucose is the main energy source for the brain and the only energy source for red blood cells
  33. what is transamination?
    the transfer of an amino group
  34. what does phosphatidic acid look like?
    has a three carbon backbone, with a phosphate group on the three carbon and acyl groups on the other two carbons.
  35. describe diacylglycerol.
    three carbon back bone two acyl groups, and an OH group on the three carbon
  36. what is triacylglycerol
    three carbon backbone with an acyl group on all three carbons.
  37. how do you get diacylglycerol?
    treat phosphatidic acid with phosphatidic acid phosphatase
  38. how can you get phosphatidic acid from diacyleglycerol?
    treat diacylglycerol with diacylglycerol kinase and consume one ATP
  39. how can you get triacylglycerol?
    treat diacylglycerol with acytrasferase and consume one acetyl-CoA to replace hydroxyl group
  40. what does ceramide look like>
    • has a long fatty acid chain double bonded to the first carbon, a nitrogen bonded to an acyl carbon off the second carbon, and an OH group off the third carbon, CH3-(CH2)12-CH--CH-CHOH-CH-CH2OH
    •           l->NH-C--O
    •                      l-R
  41. what is this compound?
    phosphatidic acid
  42. what is this molecule?
  43. what is this structure?
  44. where does cholesterol biosynthesis primarily occur?
    in the liver
  45. explain stage one of cholesterol synthesis.
    • condensation of three acetyl-CoA units to form 6C HMG-CoA
    • reduce to 6C mevalonate
    • activation with 3 molecules of ATP
    • decarboxylation to activated 5C isoprene (isopentyl phosphate)
  46. describe stage two of cholesterol synthesis.
    • condense two isoprene to form geranyl pyrophosphate.
    • add another five carbon isoprene to form farenesyl pyrophosphate
    • condense two farenesyle pyrophosphates to make one squalene molecule
  47. what is stage three of cholesterol biosynthesis?
    further modification, cyclization to lanosterol
  48. what is this?
  49. what is this?
  50. what is this?
  51. what is this?
  52. what is this?
  53. what compound do all steroidal hormones come from?
  54. how do we get estradiol?
    from testosterone
  55. what is the active form of testosterone?
  56. what is this?
  57. what amino acids are part of the alpha-ketoglutarate family?
    glutamate, glutamine, proline, arginine, lysine
  58. glutamate, glutamine, proline, arginine, and lysine are of which metabolic intermediate group?
  59. the aspartate family has which amino acids?
    aspartate, asparagine, methionine, threonine, isoleucine, lysine
  60. the amino acids aspartate, asparagine, methionine, threonine, isoleucine, lysine are of which family?
  61. the pyruvate family has what amino acids?
    alanine, valine, leucine
  62. alanine, valine, leucine are from which family?
  63. 3-phosphoglycerate g=family has what amino acids?
    serine, glycine, and cysteine
  64. the amino acids serine, glycine, and cysteine are from which family?
    3-phosphoglycerate family
  65. phosphoenolpyruvate and erythrose-4-phosphate have which amino acids associated?
    the aromatic amino acids, phenylalanine, tyrosine, and tryptophan
  66. the aromatic amino acids, phenylalanine, tyrosine, and tryptophan are of which family?
    the phosphoenolpyruvate and erytrose-4-phosphate family.
  67. how is histadine synthesized?
    from PRPP (5-phosphoribosyl-1-pyrophosphate) and ATP
  68. when is chorismate used?
    when forming the aromatic amino acids, phenylalanine, tryptophan, and tyrosine
  69. what is this?
  70. what amino acids are only ketogenic?
    leucine and lysine
  71. which amino acids are both keto and glucogenic?
    isoleucine, phenylalanine, threonine, tryptophan, and tyrosine
  72. what is this?
  73. where is ornithine used?
    in the urea cycle
  74. what is ornithine?
    it is an amino acid not used in protein synthesis
  75. what is this?