Lab 3.1: Bacteria Motility Flashcards
What allows observation of living cells to determine motility?
-simple wet mounts
-hanging drop technique
What else can be observed other than motility?
-cell size and shape
-arrangement
-binary fission
Wet mount preparation is made by:
-placing a drop of water on a slide and covering it with a cover glass
-since no stain is used, most cells are transparent
Motility can be observed at a ?? or ??-dry magnification, but viewing must be done quickly because the preparation will dry out in ??-?? minutes
-low or high
-15-20 minutes
Swimming bacteria will move ?? of one another, either in a straight line, ??, or random path
-independently
-zigzag
A hanging drop preparation allows a ?? observation of the specimen because?
-longer
-it does not dry out as quickly
Brownian motion:
-created by collisions between cells and water molecules
-cells will appear to vibrate in place
What kind of cells should exhibit Brownian motion?
-nonmotile cells
Complications that can happen when observing wet mounts or hanging drop:
-cells are not moving because they are stuck to glass
-cells are streaming across the field in the same direction
-cells are packed together and not moving
True or False:
A hanging drop is best viewed with as much illumination as possible.
-false
True or false:
Bacterial motility using a wet mount preparation can be observed even an hour or so after the specimen has been prepared
-false
Select all the cellular features from bacteria that can be observed when using a wet mount and/or hanging drop preparations. (5)
-binary fission
-size
-morphology
-motility
-arrangement
Simple wet mount and hanging drop preparations allow observation of ______________________ to determine ______________________.
-living cells
-motility
True or False:
You can easily observe bacterial flagella using both the wet mount and hanging drop preparations.
-false
True or False:
A bacterial specimen that has been heat-fixed and stained is useful to determine motility.
-false
