Prince George Community College » Biology » Bio 2010 - Microbiology » Summer 2023

Question #1

What cellular structure cause the different results after Gram staining?

A. Mycolic acid

B. Cell wall

C. Flagella

D. Cytoplasm

E. Cell membrane

Question #2

You forgot to use the safranin in your Gram staining. Which of the following would be a possible consequence?

A. Gram positive will turn purple

B. Both gram positive and Gram negative will appear purple

C. Both Gram positive and Gram Negative will appear pink

D. Gram negative will not be stained

Question #3

Which of the following are the correct order of chemicals used in Gram staining?

A. Iodine, Acetone-alcohol, crystal violet, safranin

B. Crystal violet, iodine, safranin, acetone-alcohol

C. Crystal violet, iodine, acetone-alcohol, safranin

D. Safranin, crystal violet, iodine, acetone-alcohol

Question #4

Which of the following is the most probable genus and species of bacteria indicated in the image above??

A. Neisseria sicca

B. Escherichia coli

C. Staphylococcus epidermidis

D. Bacillus subtilis

Question #5

Which of the following is the Gram's destain or bleaching reagent?

A. Carbolfuchsin

B. Acetone- Alcohol

C. Safranin

D. Loeffler's methylene blue

E. Crystal violet