Bacterial Colony Morphology

  1. What are the different qualities we look at for bacterial colony morphology?
    • form or shape
    • margins
    • elevation
    • texture
    • color
  2. How do we grow bacteria?
    bacteria can be isolated and grown on or in either solid media or liquid media
  3. What are the two different types of media?
    • solid media
    • liquid media
  4. How to we place bacteria on agar plate?
    "streak out" the bacteria onto the agar
  5. What is a pure culture?
    agar plate or broth tube contains only one type of bacteria all descending from a common ancestor
  6. What is a mixed culture?
    agar plate or broth tube contains more than one type of bacteria
  7. Can a mixed culture become a pure culture?
    yes, you can transfer cells from a single pure colony to begin a pure culture on another agar plate or in a broth tube
  8. How do we classify form or shape of bacterial colonies?
    • punctiform
    • circular
    • filamentous
    • irregular
    • rhizoid
    • spindle
  9. How do we classify elevation of bacterial colonies?
    • flat
    • raised
    • convex
    • pulvinate
    • umbonate
  10. How do we classify margins of bacterial colonies?
    • entire
    • undulate
    • lobate
    • erose
    • filamentous
    • curled
  11. Define punctiform.
  12. Define rhizoid.
    root-like, branched like roots
  13. Define pulvinate.
    very convex
  14. Define umbonate.
    raised in the center (like a belly button)
  15. Define erose.
    irregularly indented
  16. What influences bacterial colony color?
    • temperature
    • nutrient supply
  17. What can we combine colony color with when we are describing it?
    optical properties - opaque, translucent, shiny, or dull
  18. What growth patterns do we look for in broth?
    • cloudiness (uniform fine turbidity)
    • flocculent (clumps)
    • sediment
    • broth surface growth
  19. What do we have to do with the tube of broth to see the surface growth?
    gently tilt the tube
  20. What characteristics do we note about the broth surface growth?
    • ring
    • pellicle
  21. How do we test for aerotolerance?
    stab inoculation of bacteria into the bottom of an agar tube and see where the bacteria grows
  22. What is obligate (strict) aerobes?
    growth only on the surface
  23. What is obligate anaerobes?
    growth only in lower tube, away from the surface
  24. What is facultative anaerobes?
    grows everywhere
  25. What is microaerophiles?
    growth just below the surface
  26. Once we have identified size, shape, arrangement, structure, and gross appearance of the bacterial colony, what are the next steps?
    • gram stain
    • enriched media
    • differential media
    • selective media
    • biochemical testing
Card Set
Bacterial Colony Morphology