lab micro

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  1. Why do we use mircoscopes?
    microbes are too small to see with the naked eye
  2. oculars
    eye peice 10xx
  3. objectives
    • low = 10x
    • high dry= 40x
    • immersion = 100x
  4. total magnification
    ocular x objective

    example 10x40= 400x high dry
  5. How to use a microscope? (tips for success)
  6. what objective you should start with?
    • 10x
    • adjust light intensity for clarity
    • dont turn the light all the way
    • reduce intensity to moderate
    • clean them
  7. What is a we mount ? And why we use this technique? And Advantages?
    • wet mount a living suspension of the organism
    • organisma are alive
    • see motility
    • cellular arrangements
    • see the size and shap
  8. what is hay infusion?
    hay infusion is a mixture of lake and and grass or hay. the mixture has O2 pumped into it facilitates the growth of microbes in the lake.
  9. Wet mount Vs smear prep?
    • wet mount
    • see motility, cell arrangement, organism is alive
    • Smear prep
    • dead organism but allow to see a specific structure
  10. Media?
    • microorganism food
    • contain all chemicals compounds necesary to support growth
    • different organisms have different requirements
  11. Types of media and what each grows?
    • two forms
    • broth liquid
    • agar solid
  12. Essential Nutrients?
    • carbon
    • nitrogen
    • sulfur
    • phosphorous
  13. complex media?
    • complex =rich media
    • for isolation of
    • tryptic soy agar
    • brain heart infusion
    • potato dextose agar
  14. Chemically defined media?
    • exact chemicals and amount is known
    • used to isolate specific groups
  15. Living tissue media?
    • made of living organism
    • growing host specific pahogen unless live on bacteria
  16. How to calculate amount of media powder given amount of water?
  17. Definition of Sterilization?
    the complete destruction of viable organisms in a given environment to prevent contamination.
  18. Type of sterilization?
    Wet Sterilization
    • autocleving
    • media and metal objects
    • steam sterilization
  19. Type of sterilization?
  20. type of sterilization?
    • heat chemicals, antibiotics
    • gasous- anything that will melt
    • plastic, petri dishes
  21. What is streak plating and its purpose?
    • a petri plate containing some type of sterile nutrient agar( tsa,BHI,
    • purpose to seperate the bacteria in mixed culture so the individual cells can be isolated
  22. when should you flamethe inocluating loop?
    Between the streaking of each sector
  23. Labeling a petri dish?
  24. What is a dillution plating and whats its purpose?
    • a method used to estimate #s of bacteria in a sample
    • purpose is to
  25. How to perform/calculate several dilutions?
  26. Define CFU?
    colony forming units
  27. Define colony?
  28. A disease or two caused by old milk?
    • Brcellosis
    • tuberculosis
  29. pour plate method?
    second method of obtaining isolated colonies by dilution
  30. Shape/form of colonies?
    • circular
    • filamentous
    • irregular
  31. elevation of colonies?
    • flat
    • raised
    • umbonate
  32. Margin of colonies?
    • entire(smooth)
    • lobate
    • fillamentous
  33. cellular arrangements?
    • diplo= pairs
    • tetras= groups of four
    • staph=clusters
    • strep= chains of three or more
  34. Oxygen requirments?
    • facultative- grow without O2
    • Aerobic- requires O2 to grow
    • Anerobic- O2 is toxic ,requires no oxygen environment to live
    • microaerophilic- O2 is toxic at atmosphere concentrations only small amount
  35. What is Smear Prep?
    a procedure used to prepare a bacterial sample for staining in which the bacteria is heat fixed to a slide
  36. What is it used for?
    staining and increasing contrast
  37. Disadvantages of smear prep?
    motility no longer be studued ditorts the cells apperance
  38. Staining Procedure?
    • if liquid broth place a loopfull of broth directly on to the slide
    • if isolated first drop of water on to slide and which a small amount of bacteria is dispersed using a loop
  39. How do you do it?
  40. Why is the gram stain useful?
  41. What are the 4 steps of the gram staining procedure?
  42. what are the difference in the outer protection between gram + and gram -?
  43. What do these cells liik like in the end?
  44. Why is a capsul useful for bacteria?
    • protections
    • act as a barrier between the cells
    • reserve cabroydrate
    • aid the cell in adhering
  45. what is a capsule?
    a viscous substance which accumulates and coats the cell and becomes the outermost layer made up of polyssacharides(few Proteins)
  46. What is a capsule Stain?
  47. What is a negative stain?
    steaming the background leaving the capsule unstained since it cant be stained.
  48. What is Schaeffer-fulton?
    stain capable to distiquish between spores and vegetative cells found primarily in the clostridium and bacillus genera
  49. What is an endospore?
    its a dorment form of the bacterium that allows it to servive lean envrionmental conditions./ spores form within the cell( vegetative cell)
  50. What bacterium form endospore?
    • the clostridum
    • bacillus genera
  51. Why do we steam?
    • its a primary stain in malachite green is forced into the spore coat.
    • To distiquish between the spore and the vegetative cell
  52. What is an acid fact bacterium?
    • stain important for differential for identifying bacteria in the gendo mycobacterium
    • large amounts of lipids and waxes in their cell wall makes them inpermeable and resistant
  53. Ziehl-neelsen stain?
    • alos known as the acid fast stain
    • allows to identify bacteria with large amounts od lipids and waxes in their cell walls
    • most commoly in the genus mycobcterium
    • will appear red-non blue
  54. Why special measures to dye them?
    due to that they are impermeable and resistant to many chemicals
  55. What special measures?
  56. what bacteria are acid fast?
    • genus
    • myobacterium
    • M.leprae
    • lepros
    • M.tuberculosis
  57. What is a selective Media?
    • has a selection agent or agents added to it prohibits the growth of some organisms
    • allows the organism of interact to grow while inhibits the growth of others.
  58. What is differential Media?
    • growth of organisms not inhibited
    • contains substances that allow different groups grow differently than others when grown on the same media
  59. Mannitol salt agar(MSA)
    • selects gram + bacteria growth
    • highest level of salts
    • mannitol and phenol red
    • when fermented turn yellow
    • non mannitol fermenters remain pink
  60. MocConkeys Agar?
    • crystal violet bile salts
    • inhibits growth of gram+
    • contains lactos and neutral red ph indicator
    • turn to red colonies
    • non lactos colonies do not change
  61. Kliglers Iron Agar (KIA)
    • determinator of varbohydrate fermentation patterns and gas production
    • determines gram - rod Enterobactericeae
  62. KIA agar slant
    inoculated with a needle( not Loop) stab then streak slant
Card Set
lab micro
exam 1
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