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Flashcards

Micro Part 3

Melanie Horne Inglês 80 flashcards

Flashcards do conjunto (80)

  1. 1What are characteristics of viruses?Parasites of humans, plants, animals and bacteria
    -Cannot reproduce or metabolize, do not grow or response to the environment
    -Small, acellular
  2. 2What is a virion?A virus particle existing outside of a cell
  3. 3What is a capsid?A protein coat surrounding nucleic acid
  4. 4What is an envelope?A phospholipid layer that provides protection and recognition for host cells
  5. 5What is the intracellular state of a virus?The capsid is removed and it exists as a nucleic acid
  6. 6What is a nucleocapsid?A nucleic acid and capsid
  7. 7How are viruses distinguished?-Genetic material
    -Size
    -Host type
    -Nature of capsid coat, envelope
  8. 8What is true of the genetic material of viruses?-Have either DNA or RNA
    -ds or ss
    -Much smaller than genomes of cells
    -Large variety in genomes
  9. 9What are capsids composed of?Composed of subunits called capsomere (can be all the same type or multiple types of capsomeres)
  10. 10What are some viral shapes?Helical
    Polyhedral
    Complex (ex: polyhedral head with tail, bullet shaped, enveloped virus with helical capsid)
  11. 11How does viral replication occur?-Dependent on host 's organelles and enzymes to produce new virons
    -Death of host cell
    -Or, lytic replication
  12. 12What are temperate bacteriophages?Undergo lysogeny: splicing into bacterial host chromosome, when bacteria divides, it also replicates viral genome.
  13. 13How do animal viruses attach to host cells?Chemical attraction
    -Glycoprotein spikes + other attachment momlecules
  14. 14How do enveloped viruses gain entry to a cell?-Endocytosis
    -Membrane bround endosome and virus bind to release viral genome
  15. 15What is positive sense rna?Same polarity as messenger RNA-If viruses have this, their RNA can function as mRNA as soon as it enters the cell
  16. 16What are negative sense RNA viruses?-Must carry an enzyme that makes positive strand from negative
  17. 17Where are most DNA viruses assembled and released?Assembles in nucleus, released into cytosol
  18. 18Where are most RNA viruses produced?The cytoplasm
  19. 19What is an episome?A virus that does not become incorperated into the host chromosome and are extracellular pieces of DNA, remain latent for a while
  20. 20What are the roles of viruses in cancer?Genes for cell division are turned off, or genes that inhibit division turned on
  21. 21What is neoplasia?Uncontrolled cell division in a multicellular animal; a mass of neoplastic cells is a tumor
  22. 22What is the oncogene theory?Protooncogenes are normally present in a cell. Repressor proteins usually keep these genes silent, but viruses may insert a promoter upstream (first hit). Second hit is the insertion of gene into repressor gene for oncogene.
  23. 23What other factors are involved in activation of oncogenes?UV light, radiation, carcinogens, and viruses
  24. 24What are viroids?-No capsid
    -Extremely small circular RNA infectious in plants
    -Appear linear due to H-bonds
  25. 25What are prions?-proteinaceous infectious agents composed of single protein, PrP
    -Resistant to inactivation by high temps, radiation, DNAses or RNAses
    -Sensitive to phenol and urea
    -Transmitted only by contact with infected tissues/secretions
  26. 26What are the two stable tertiary structures of PrP?Cellular PrP: normal functional structure with alpha-helices
    Prion PrP: Disease-causing form with beta sheets called
  27. 27What happens in prion diseases?Fatal neurological degeneration
    -Large vacuoles from in brain
    -Scrapie, Mad cow disease, Kuru, Creutzfeld-Jakob disease
  28. 28Why was smallpox effectively eradicated?-No animal reservoirs
    -Obvious symptoms, quick diagnosis and quarantine
    -Stable vaccine
    -No asymptomatic cases
  29. 29Which type of RNA can act directly like mRNA when it enters a cell?positive RNA
  30. 30What is a problem with the Oral polio vaccine?Small possibility that virus can mutate back to wild-type. Now we only use the inactivated vaccing
  31. 31Paralytic polio was once considered a disease of developed countries becausechildren in developed countries are not exposed to the virus until they are older and maternal Ab has waned
  32. 32What are the two types of viruses?1) Viruses that are primarily oncogenic
    2) viruses that are primarily immunosupressive
  33. 33Why do retroviruses do not conform to the central dogma?They have an RNA genome and use reverse transcriptase enzyme to make dsDNA which is spliced into the host cell.
  34. 34Which cells does HIV infect?Cells with CD4 receptors
    Macrophages and lymphocytes
  35. 35What is the structure of HIV?2 identical ssRNA within a helical capsid, surrounded in an envelope
  36. 36How does HIV attach and infect cells?Uses CXCR4 is a co-receptor used in T cell infection
    CCR5 is co-receptor used in macrophage infection
  37. 37How does HIV replicate?d
  38. 38What are the stages in HIV infection?h
  39. 39What is a common manifestation of AIDS?Oral candidiasis, Kaposi's sarcoma, cronic wasting disease
  40. 40What is antigenic drift?Happens over the course of influenza viral replication because RNA polymerase does not proofread. Point mutations change thing slightly
  41. 41What is antigenic shift?Cells is infected by two different strains of influenza virus, genes and antigens from different viruses are combined. A novel variant emerges with different assortments of H and N types
  42. 42What is applied microbiology?Metabolic activities of microorganisms that are used for commercial processes
  43. 43What are the two fields of microbiology?1) Food microbiology
    2) Industrial microbiology
  44. 44What is fermentation in relation to food production?Any desirable change that occurs to a food or beverage as a result of microbial growth
  45. 45What is spoilage?Any unwanted change to a food that could occur for various regions. Could include growth of pathogenic organisms, the general presence of any microorganisms in the food
  46. 46What are starter cultures?Known microoganisms which perform specific fermentation consistently
  47. 47What is the process of cheese making?1) Pasteurized milk
    2) Add starter culture (rennin)
    3) Coagulation of milk proteins
    4) Press curds, discard whey (liquid waste)
    5) Inoculate curds with secondary cultures to get different cheese varieties
  48. 48How is wine made? (Enology)1) Grapes, crushed into juice (must)
    2) Yeast (S. ellipsoideus) starter cultures ferments must
    3) Clarification, aging,
    4) Bottled
  49. 49How does beer brewing work?1) Barley germinates, activates amylases that converts starch into simple sugars
    2) Barley dried and crushed to produce malt
    3) Mash malt with warm water, solids removed to produce wort. Addition of hops
    4) Remove hops, add yeast culture (pitching)
    5) Wort ferments into beer, aging, filtration
  50. 50What is Sake?Called rice wine, but is more like rice beer. Has a alcohol content of about 14%
  51. 51What is brandy?Distilled wine
  52. 52What is whiskey?Distillation of malt brews
    (rye = mostly rye)
    (bourbon = mostly corn)
  53. 53How is vinegar made?Beechwood shavings added to a generator. Add a starting material over top (wine), aerobic process where oxygen is added. Ethanol is oxidized to acetic acid.
  54. 54How are mushrooms produced?Most grown underground or in caves.
  55. 55What are perishable foods?Nutrient rich, moist and unprotected by rinds or coverings, must be kept cold
  56. 56Semi-perishable foods?Can be stored in sealed containers for moths without spoiling
  57. 57What are nonperishable foods?Usually dried or canned foods that can be stored without spoiling
  58. 58What are three methods to prevent food spoilage?1) Pasteurization
    2) Lyophilization
    3) Gamma radiation
  59. 59What are preservatives to keep food?Salt and sugar remove water
    Garlic inhibits the antimicrobial compound allicin
    Benzoic acid in cranberries interferes with enzymatic functions
  60. 60What are the two types of food bourne illness?1) Food infections - from the consumption of living microbes
    2) Food intoxications - caused by the consumption of microbial toxins rather than the microbe itself
  61. 61What is the most common cause of bacterial gastroenteritis?Campylobacter jejuni
  62. 62What are primary metabolites?Produced during active growth and metabolism, required for production of new organisms or are by-products of active metabolism
    ex: alcohol or sugar
  63. 63What are secondary metabolites?Produced after cells have left log phase of growth and entered stationary phase; substances are not immediately needed for growth
    ex: penicillin
  64. 64What useful industrial products are made by E. coli?Insulin and Taxol
  65. 65What is a natural insecticide produced by Bacillus thuringiensis?Produces a crystal toxin that only dissolves in an alkaline environment
    -When insect chew on the leaves, they will rapidly die
  66. 66How is citric acid produced?-Industrially by a fermentation using Aspergillus niger
    -Medium must be iron-deficient
  67. 67What is potable water?Considered safe to drink, not completely devoid of all organisms, just present at an acceptable level
  68. 68What are the four stages of drinking water treatment?1) Allow water to sit - sedimentation and flocculation
    2) Filtration
    3) Microbial filtration
    4) Disinfection: chlorine, ozone or UV light
  69. 69What are some techniques used for water quality testing?-Most probably number
    -Membrane filtration
    -ONPG and MUG
    -PCR
  70. 70What does a high BOD mean?There is a lot of waste contamination in a water sample
  71. 71What is the biochemical oxygen demand (BOD)?A measure of the amount of O2 required by aerobic bacteria to fully metabolize organic wastes in water; an indirect measure of the amount of organic wastes in water
  72. 72How does sewage treatment work?1) Sedimentation
    2) Secondary treatment, microbial degradation of organic matter
    3) Chemical treatment, chlorination, disinfection of liquid
    4) Treatment of sludge involves anaerobic digestion and dried sludge used for agriculture
  73. 73What is a septic tank?Often used when houses are not connected to the sewer line; equivalent to primary treatment
  74. 74What is bioremediation?Uses organisms to clean up toxic, hazardous and recalcitrant compounds by degrading them to less harmful forms
  75. 75What is natural bioremediation?Encourages growth of microbes by adding water or nutrients
  76. 76What is artificial bioremediation?Microbes are genetically modified by recombinant DNA tech to degrade specific chemicals
    ex: Pseudomonas can be used to degrade crude oil
  77. 77What are CDC select agents?-Regulations for use and transfer of these agents, how they used
    -Special designation for problematic teir 1 agents
  78. 78What does the release of endotoxin cause?-Triggers leukocytes to release cytokines
    -blood-clotting reactions
    -Complement
  79. 79What are the three types of Enterobacteriaceae and how are they distinguished?1) Coliforms ferment lactose, usually part of normal microbiota
    2) Non-coliforms do not ferment lactose
    3) Frank pathogens, not part of normal microbiota (ex: Salmonella)
  80. 80—

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FlashCards sobre Micro Part 3, criado por Melanie Horne em 07-08-2018.
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Melanie Horne
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