Micro Ch4

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  1. Magnification makes an object
    appear larger and remain the same size
  2. What could have been the most precisely resolved object seen under a Leeuwenhoek microscope?
    a red blood cell
  3. Why do most microbes have poor contrast?
    they are colorless
  4. Oil immersion lenses help microscopists increase
    magnification and resolution
  5. For a light microscope, the limit of resolution is determined by
    the wavelength of visible light
  6. Living microbes can best be viewed using which type of microscopy?
    Phase-contrast microscopy
  7. The resolving limit of the best light microscope under the best of contidtions is __________, whereas that of a scanning electron microscope is ______________.
    200 nm, 10nm
  8. What is the major difference between SEM and TEM?
    SEM produces a 3D image
  9. If you were performing  a Gram stain on a bacterial sample and forgot the step that uses ethanol and acetone, what color would the cells be at the end of the Gram staining procedure?
  10. The most appropriate stain to use to indentify a bacterial species that produces thick, waxy cell walls is the
    acid-fast stain
  11. In staining, the purpose of a mordant is to
    bind dyes to make them less soluble
  12. The major difference between the stains used in electron microscopy and those used in light microscopy is that stains for the electron microscope are
    heavy metals and electron dense
  13. The goal of modern classification schemes has shifted from a simple desire to catalog organisms to a desire to
    • understand phylogenetic relationships
    • determine common acestors
    • determine evolutionary relationships
  14. In the domain system of nomenclature, differences between organisms are based on
    rRNA sequences
  15. Why are viruses NOT included among the three domains or five kingdoms of modern taxonomy?
    a.they are acellular
    b.too small to be readily studied
    c. they were not included in older taxonomic systems so should not be included in new systems
    d. none of the above apply to viruses
    d. none of the above apply to viruses
  16. Empty magnification produces images that are faint and blurry because the image lacks sufficient_________ and ______.
    contrast, resolution
  17. Fluorescent microscopes have __________ (better/worse) resolution than standard bright-field microscopes because UV light has a __________ (longer/shorter) wavelength than visible light.
    better, shorter
  18. The two types of microscopy that produce direct 3D images for viewing are _________ and __________.
    differential interference, scanning electron
  19. Electron microscopy is most useful for viewing a cell's ________________, those parts of the cell that can't be seen any other way.
  20. Staining is useful because it increases ____________ between structures or a specimen and its background; this, in turn, allows for better ____________.
    contrast, resolution
  21. Anionic chromophores are called _________ dyes and bind to ___________ (acidic/basic) structures, whereas cationic chromophores are called __________ dyes and bind to (acidic/basic) structures
    Acidic, basic, basic, acidic
  22. In order for cells exposed to a negative stain to be stained themselves, a ___________ must be added, otherwise the cells remain colorless.
  23. Taxonomy consists of three parameter: ___________, __________, and _________.
    Classification, nomenclature, identification
  24. In _________ tests, antiserum is mixed with patient samples.  Antiserum contains __________ that recognize microbial __________.
    agglutination, antibodies, antigens
  25. Refers to the use of light or electrons to magnify objects
  26. distance between two corresponding parts of a wave
  27. apparent increase in size of an object and is indicated by a number followed by an "x"
  28. the ability to distinguish objects that are close together; also called resolving power
  29. lenses ability to gather light
    numerical aperture
  30. used to fill the space between the specimen and a lens to reduce light refraction and thus increase the numerical aperture and resolution
    immersion oil
  31. most common type of microscope; prevents light from directly entering the objective lense
    bright-field microscope
  32. two types of bright-field microscopes
    • simple microscope - single lens; similar to a magnifying glass
    • compound microscope - uses a series of lenses
  33. parts of a compound microscope
    • revolving nosepiece - where objective lenses are mounted
    • ocular lenses - lenses closes to the eyes
    • condenser lenses - lie beneath the stage of the microscope and direct light through the slide
  34. photograph of a microscopic image
  35. microscope that utilizes a dark field stop in the condenser that prevents light from directly entering the objective lens; pale objects are best observed with this microscope
    dark-field microscope
  36. uses fluorescent dyes in conjunction with UV lasers to illuminate the fluorescent chemicals in only a single plane of a specimen at at time
    confocal microscope
  37. generates a beam of electrons that passes through a thinly sliced, dehydrated specimen, through magnetic fields that changes the electrons energy into visible light
    TEM (transmission electron microscope)
  38. thing film of organisms on a slide
  39. passing a slide through a flame
    heat fixation
  40. applying a chemical to a slide
    chemical fixation
  41. colored portion of a dye
  42. composed of a single basic dye such as crystal violet and involve no more than soaking the smear in the dye and rinsing
    simple stain
  43. use more than one dye so that different cells, chemical,s or structures can be distinguished
    differential stains
  44. purple staining
    Gram-positive cells
  45. pink staining
    Gram-negative cells
Card Set:
Micro Ch4
2013-01-25 02:28:52

Microscopy, Staining, and Classification
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