From handouts & books
College: First year
Standard plate count (SPC)
DAPI or AODC staining & microscopy
Spectroscopy method of counting (how it works)
based on turbidity. Optical density used to describe the turbidity of a culture. The Spec 20 can quantify the OD of a culture indirectly by measuring the amount of light that can pass through a a culture (percent transmittance %T). The higher the OD the lower the %T (indirectly proportional, the higher the OD the higher the turbidity (directly proportional)
If you were given a stock culture that was really old, would you expect the SPC to be higher or lower?
Why shouldn't you use a plate that has 10 colonies to calulate the number of cells in the starting culture?
Which counting method would you use if you need isolated colonies from a soil sample and why?
Why is it desirable that microscope objectives be parfocal?
What controls the amount of light reaching the oculars?
What effect does increased magnification have on the field of vision?
What does the "ubiquity of microorganisms" refer to ?
What are the objective powers and names?
Primary purpose of: deeps, slants, broths?
Resolution (or resolving power)
When using low-power lense, the iris diaphragm should be...?
Darkfield microscopy is valuable for observing...?
What is the usual % agar and what is a lower % used for?
Slants vs. plates
Growth patterns in agar & broth
-Colony shape--circular, irregular, punctiform (tiny)
-Margin--entire(smooth, undulate, lobated, filamentous, rhizoid (branched root)
-Elevation--flat, raised, convex, pulvincate (very convex_, umbonate (raised in center)
-Texture--moist, dry, mucoid
-Pigment--opaque, translucent, shiny, dull
-BROTH--pellicles (dots), sediment (at bottom), uniform fine turbidity, flocculent (clump)