Question

1) Alkaline dyes have ______________________ chromophores.

2. They stain because bacteria have an overall ____________________.

3. The standard parameters for sterilization in the autoclave are ___________________, __________________ for _____________________.    

4) With what kind of cultures must we work, so we have reliable, valid tests?

5). Name 3 distinct species that retain the primary dye in the Gram stain.

6). Name 3 distinct species that display the counterstain in the Gram stain?

Answer 1

1. Alkaline dyes have basic chromophore
2. They stain because bacteria have an overall acidic pH
3. The standard parameters for sterilization in the autoclave are - 121oC at 15 pounds PSI pressure for 30 minutes.
4. We must work with pure cultures in order to get valid and reliable test results.
5. Organisms retaining the primary dye of gram stain (Gram Positive) include: Staphylococcus aureus; Streptococcus pneumoniae; Bacillus subtilis; Clostridium tetani
6. Organisms that get counter stained in gram stain (Gram Negative) include: Escherichia coli; Salmonella typhi; Pseudomonas aeruginosa; Neisseria gonorrhoeae