MMG 301

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MMG 301
2014-02-23 12:04:24
MMG 301

test two
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  1. what is the difference in gram positive bacteria peptidoglycan and gram negative bacteria peptidoglycan
    gram negative bacteria peptidoglycan does not have glycine between two tetrapeptides.
  2. what is the function of the Mot protein in the bacterial flagellum?
    to cause the rod and rings to rotate using the proton motive force.
  3. in a chemostat culture, bacterial cultures are constantly maintained in:
    exponential phase
  4. the ____ controlling the stringent response in period of starvation are produced in response to a signal from the ____ telling the cell that they are out of amino acids for protein synthesis
    alarmones / ribosomes
  5. what is true about a lipopolysaccharide (LPS). (4 things).
    • the LPS is the major structural component of the outer leaflet of the outer membrane in gram-negative bacteria
    • the LPS is composed of lipid A, the core polysaccharide, and O-specific polysaccharide
    • the LPS is often called endotoxin in pathogenic bacteria
    • the LPS blocks certain toxic compounds from entering the cell
  6. what is true about bacterial endospores (2)
    • complexes of dipicolinic acid and Ca2+reduce water availability in the spore and stabilize the endospore's DNA
    • small acid-soluble spore proteins are degraded as a source of amino acids during spore germination
  7. what is the function of carboxysome compartments in bacteria?
    to concentrate CO2 enough to allow CO2 fixation by RubisCO
  8. true or flase. autoinducers produced by bacteria in quorum sensing are only produced at high bacterial densities.
  9. what mechanism makes a bacterial species grow faster when the temperature increases from minimum temperature to the optimum temperature of growth
    enzymatic reactions occur at faster rates
  10. glycogen granules are degraded by bacterial cells:
    as sources of carbon and energy in periods of starvation
  11. what happens if lysosome is added to gram-positive bacteria in a hypotonic solution.
    lysosome breaks down the beta-1,4 glycosidic linkages in peptidoglycan, water enters the protoplast, and the bacteria burst open   poof
  12. which pathway is blocked by tetracycline antibiotics?
    protein synthesis
  13. a defined medium containing KH2PO4, K2HPO4, (NH4)2SO4, MgSO4, CaCl2, glucose, microelements, histadine (=an amino acid) and thiamine (=a vitamin) will allow which strain or strains of Escherichia coli to grow?
    strains unable to synthesize histadine, thiamine or both
  14. true or false. the decimal reduction time is the time it takes for 90% of the initial bacteria to be killed
  15. fimbriae are considered virulence in certain bacteria because... (2)
    • they show tissue and host specificity in colonization
    • they recognize and bind to specific carbohydrates on host cells
  16. a bacterial culture has a generation time of 30 min. in a complex medium at 370C. if the starting culture has 102 cfu/mL, approximately how long will it take the culture to reach a density of 105 (100000) cfu/mL?
    • approximately 330 min (closer to 300)
    • 100-30
    • 200-60
    • 400-90
    • 800-120
    • 1600-150
    • 3200-180
    • 6400-210
    • 12800-240
    • 25600-270
    • 51200-300
    • 102400-330
  17. true or false. the bacterial chromosome needs about 1000-fold compaction to fit inside the cell
  18. what bacterial cell division protein pulls DNA molecules into daughter cells?
  19. what bacterial cell division protein locates where new cell wall is produced and gives bacilli their rod shape?
  20. what bacterial cell division protein forms a spiral inside the cell membrane, oscillates from pole to pole, and inhibits the formation of FtsZ ring?
  21. what bacterial cell division protein oscillates from cell pole to cell pole, and pushes MinCD aside
  22. what bacterial cell division protein forms a ring in the center of the cell and recruits the divisome?
  23. you inoculate a fresh medium (called medium a) with a culture grown in medium a and harvested in the middle of the exponential phase. how long will the lag phase be?
    • there should be no lag phase at all.
    • the bacteria are healthy having been harvested mid exponential phase and have already been accustomed to the medium so there is no adaptation or coping.
  24. the periplasm is: (2)
    • the region between the cytoplasmic membrane and the outer membrane of gram-negative bacteria
    • absent in gram-positive bacteria
  25. why cant non-chemotherapeutic agents be used internally inside the human body?
    • they are non-selective agents
    • they are too toxic
  26. motility of a bacterium away from a chemical repellent is called ____ and random reorientation in the absence of flagellar rotation is called ____
    chemotaxis / Brownian motion
  27. the most suitable method to sterilize a heat-sensitive liquid reagent in a laboratory is:
    membrane filtration
  28. what is true about isoniazid? (4)
    • it blocks mycolic acid production, which is a pathway unique to mycobacteria
    • it is a synthetic drug
    • resistance to isoniazid develops quickly
    • it is the best antimicrobial treatment against tuberculosis
  29. true or false. neuraminidase inhibitors are good anti-HIV drugs
  30. transport of solutes into the bacterial cell by simple passive diffusion works when:
    the solute concentration in higher outside than inside the cell
  31. if you used a spectrophotometer to measure bacterial cell density in a culture that has high cell density, the optical density on the spectrophotometer would:
    most likely underestimate the cell density
  32. which medium would be the most suitable to culture a fastidious bacterium isolated from an alkaline (=basic, high pH) environment?
    pH around 10, yeast extract, several amino acids, purines, pyrimidines, vitiamins, and glucose
  33. what behavior is known to be controlled by quorum sensing in staphylococcus areus?
    production of toxins and proteases needed for dissemination
  34. true or false. unidirectional flagella push the bacterial cell forward by rotating counterclockwise (CCW) and pull the cell backward by rotating clockwise (CW)
  35. which mechanism spreads antibiotic resistance easily from one bacterial species to another?
    transfer of R plasmids
  36. what is true about magnetosomes?
    • they form by invagination of the cytoplasmic membrane
    • they are filled with magnetic salts of iron, magnetite, or greigite
    • magnetosomes are organized in one or more chains by cytoskeletal filaments
    • they are found mostly in bacteria that grow best at low O2 concentrations
  37. which factor is the least likely to affect the generation time of a bacterial culture growing exponentially?
    the culture volume
  38. what type of bacterial flagellation is represented by a cluster at one end of the cell?
  39. what type of bacterial flagellation is represented by clusters at both ends?
  40. what type of bacterial flagellation is represented by a single one on one end?
    monotrichous polar
  41. what type of bacterial cell flagellation is represented by a single one on a side?
    monotrichous lateral
  42. what type of bacterial flagellation is represented by random placement around the cell?
  43. the function of braun's lipoprotein is?
    to anchor the outer membrane to the peptidoglycan of gram-positive bacteria
  44. which type of microorganism has a cell membrane that contains teichoic acid, peptidoglycan layer and a cytoplasmic membrane?
    gram-positive bacteria
  45. pseudomurein is a characteristic of the walls of ____
    some archaea
  46. ____ is the source of energy for glucose uptake by the phosphotransferase system and ____ is the source of energy for the transport of maltose by ABC transporter
  47. what happens if lysosome is added to gram-positive bacteria in an isotonic solute solution?
    lysosome breaks down beta-1,4 glycosidic linkages in peptidoglycan and releases the protoplast into the solution
  48. which proteins are responsible for the passive diffusion of small hydrophilic molecules through the outer membrane of gram-negative bacteria
  49. which of the following is not a function of bacterial capsules?
  50. true or false. the flagellar motor rotates the rod and rings in the basal body.
  51. true or false the major protein subunit of the flagellar filament is called flaggelin.
  52. true or false. flagella rotate at a constant speed
  53. true or false. bacterial flagella use the proton motive force for energy for rotation
  54. true or false. flagella elongate at the distal end of the filament.
  55. true or false. bacteria with peritrichous flagella reorient by Brownian motion.
    FALSE-- they reorient by tumbling
  56. what bacteria flagellation reorients by Brownian motion? (2)
    monotrichous polar/lateral
  57. proteins from the cytoplasmic membrane involved in sensing chemical gradients during chemotaxis are called ____
  58. which nucleotide-specific proteins are involved in compacting the bacterial chromosomeal DNA enough o fit in a bacterium cell? (2)
    • DNA gyrase
    • topoisomerase
  59. in which bacteria are carboxysomes found?
  60. which bacterial storage polymer has applications in multiple industries
  61. LB-Gal agar is a medium containing tryptone, yeast extract, NaCl, and X-gal (turns blue with beta-galactosidase activity) what type of medium is this? (2)  (do not count "rich")
    • differential
    • complex
  62. which of the following macromolecules represent the largest fraction of a cells dry weight?
  63. the technique used to generate isolated colonies on an agar plate medium is?
    streak plating
  64. which molecule is synthesized and accumulates specifically during sporulation, helps dehydrate the spore, and helps stabilize the spore DNA against heat denaturation
    dipicolinic acid
  65. what is the third stage of endospore formation
    engulfment of the fore spore by the mother cell
  66. what is the first stage of endospore formation
    asymmetric cell division
  67. what is the fourth stage of cell division?
    cortex formation
  68. what is stage five of spore formation?
    coat formation, Ca2+, SASPs, dipicolinic acid
  69. the filtration method for viable cell count is often used to ____
    monitor the quality of water
  70. lookin for OD of a culture you take three measurments, undiluted culture is 2.2
    5-fold dilution is 4.9
    10-fold dilution is 5.6
    which measurement should you use?
    the OD of the 10-fold dilution
  71. you want to study a bacterial culture when it is in its healthiest and most uniform phase of growth, when do you harvest it?
    during the exponential phase
  72. true or false. at low concentration, the limiting nutrient in medium affects both the growth rate and growth yield of a bacterial culture
  73. true or false. stringent control Is triggered by starvation
  74. true or false. ribosomes sense that a cell is running out of amino acids and triggers alarmone synthesis
  75. true or false. stringent control up-regulates synthesis.
  76. true or false. stringent control up-regulates the synthesis of stationary phase inducible proteins.
  77. true or false. stringent control down-regulates the number of ribosomes in the cell
  78. true or false. autoinducers used by bacteria for quorum sensing are produced only at high bacterial population densities.
  79. in pathogenic bacterial species, what is most likely to be regulated by quorum sensing?
    DNA replication, Toxin production, Peptidoglycan synthesis, Carotenoid synthesis, or Accumulation of glycogen granules
    toxin production
  80. true or false. biofilms are formed of microbial cells that are immobilized in a polymer matrix and grow on a given surface
  81. true or false. biofilms are made of biodegradable plastics such as polyhydroxybutyrate
  82. true or false. biofilms are formed of dead cells that attach to the bottom or sides of a growth flask
  83. true or false. biofilms are rare in the environment.
  84. true or false. biofilms are formed of polymers secreted as waste products by microbes
  85. what mechanism allows bacterial species to grow faster when the temperature hanges from minimal to optimum?
    enzymatic reactions occur at faster rates
  86. what most likely happens in bacterial species that grow in a hyperosmotic environment?
    they accumulate large concentrations of compatible solutes.
  87. you can only autoclave at 100 Celsius, you want to sterilize a small volume of media used to grow bacteria A, bacteria A has a decimal reduction time of 5 min at 100 Celsius, what would the recommended time for autoclaving be?
    60 min
  88. which two fungal pathways can be targeted without doing too much damage to the patient?
    1: cholesterol synthesis
    2: cell wall synthesis
    3: ergosterol synthesis
    4: protein synthesis
    5: respiration
    2, and 3
  89. what do tetracycline antibiotics do?
    bind to ribosomes and inhibit protein growth
  90. explain why the anammox process takes place in a separate compartment within the cell.
    one intermediate in the process, hydrazine, is highly toxic to cells, the cells protect themselves from this intermediate by having the process in a separate compartment