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BIMM 120 CH 2

  1. Resolution
    the smallest distance by which two objects can be separated and still be distinguished
  2. resolution of the human retina
    150um
  3. detection
    the ability to determine the presence of an object
  4. maginification
    increase in the apparent size of an image to resolve smaller separations between objects
  5. Order from smallest to largest: RBC, staphyococcus aureus, paramecium, bacillus megaterium, E. coli
    S. aureus<E. coli<B. megaterium<RBC<paramecium
  6. T/F - Light is part of the spectrum of electromagnetic radiation
    True!
  7. For electromagnetic radiation to resolve an object, what three conditions must exist?
    • Contrast
    • Wavelength smaller than the object
    • magnification
  8. What limits the ability of what we can see with a microscope?
    resolution
  9. Bright-field microscopy
    dark image of an object surrounded by a light background
  10. Total magnification on compound microscope
    magnification of ocular lens x magnification of objective lens
  11. fixation
    • cells are made to adhere to a slide in a fixed position with heat or chemicals
    • usually kills the cells
  12. simple stain
    only stains cells and not background
  13. differential stain
    stains one kind of cell
  14. Gram stain procedure
    • methanol to fix
    • crystal violet stain
    • iodine (binds stain to gram positive)
    • ethanol wash
    • safranin (counterstains gram negative)
  15. acid-fast stain
    carbolfuchsin used to stain Mycobacterium species
  16. spore stain
    malachite green used to detect spores of Bacillus and Clostridium
  17. negative stain
    capsule is more visible
  18. fluorescence microscopy
    • fluorescent molecules absorb light of defined wavelength
    • emits light of lower energy, longer wavelength
  19. fluorophore cell specificity can be determined in what three ways?
    • chemical affinity for a cellular component
    • labeled antibodies that bind to specific cellular components
    • DNA hybridization to specific DNA sequences
  20. Dark-field microscopy
    • light image on dark background
    • flagella and thin bacteria
  21. phase-contrast microscopy
    • constructive and destructive interference
    • live unstained cells and cellular organelles of larger eukaryotic cells
  22. T/F - samples are killed in electron microscopy
    True, samples are coated with heavy metal
  23. TEM vs SEM
    • TEM reveals internal structures
    • SEM external features
  24. x-ray crystallography
    determine position of individual atoms in a molecule
Author
andrewlee22087
ID
316998
Card Set
BIMM 120 CH 2
Description
bacteriology
Updated

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