Microbiology Lab Report 3 – Spring 2016
1.
How does smear preparation of cells from a liquid medium differ from preparation of cells from a solid medium?
2.
Why is it important to limit the number of cells on a slide?
3.
What is the arrangement and cell morphology of B. megaterium?
4.
What is the arrangement and cell morphology of S. epidermidis?
5.
Why do acidic dyes not stain bacterial cells?
6.
How does the age of a culture affect the Gram stain reaction? What is an optimum age for a valid Gram reaction?

7.
Matching Questions: Match the expected result (purple, pink, or colorless) to the following descriptions of Gram stained cells. Consult your chart at the beginning of this lab if you need help remembering the correct Gram reaction for each species. Choices may be used more than once. a.
Staphylococcus aureus before the primary stain? b.
Pseudomonas aeruginosa after the primary stain? c.
Staphylococcus aureus after decolorization? d.
Pseudomonas aeruginosa after decolorization? e.
Bacillus megaterium after adding the counterstain? f.
Escherichia coli viewed with the microscope if you forgot to apply safrain? g.
Escherichia coli viewed with the microscope if you forgot to apply the decolorizer? h.
Bacillus megaterium viewed with the microscope if you forgot to use the iodine?