Ex 3: Simple Stains, Hanging Drop, and Wet-Mount Preparations


Terms in this set (...)

Define acidic dyes
anions (neg) that combine with cations of a base in the stained cell to form a salt
Define Basic dyes
possess cations that combine with an acid the stained material to form a salt
Why are specimens to be stained suspended in sterile or distilled water?
we use sterile water because to avoid false result by microorganism having in the water and same reason for distilled also to avoid impurities like crystals of some metal ions and also to avoid other microorganisms
which of the microscope objectives is most satisfactory for studying bacteria in stained preparations? In wet mount preparations? why?
List and define the basic shapes of bacteria. What are the dimensions of an average bacillus in micrometers? In centimeters
spherical, rod, spiraled. 0.5-1.0 micrometers. .0005-.001 centimeters.
List at least three types f bacteria whose names reflect their shapes and arrangements, and state the meaning of each
coccus-round shaped bacteria
bacilli-rod shaped bacteria
spirillium-spiral shaped bacteria
for what reasons do we need to stain bacteria?
to view them easier and clearly, to have contrast in order to identify cell morphology of the bacteria.
Examine color plates 1-8 and describe the morphology of bacteria in each one
How does true motility differ from Brownian movement?
Brownian movement results from random motion of water molecules bombarding the bacteria and causing them to move. True motility and self propulsion involves the 3 modes of motility.
What morphological structure is responsible for bacterial motility?
Why are wet and hanging drop preparations discarded in disinfectant solution or a biohazard container?
preparation has micro-organisms which can interact with the people or environment surrounding them
How does a stained preparation compare with a hanging drop or wet mount for studying the morphology and motility of bacteria?
it provides a an undistorted view of natural cell groupings and of individual cell size and shape.
Can you save a wet mount to look at during a later class period?
No because it will dry out