California State University, Fullerton » Biology » Biology 302 - General Microbiology » Spring 2022

Question #1

At the conclusion of a properly executed Gram stain, Gram - bacteria will appear

A. purple/violet

B. colorless

C. pinkish/red

Question #2

Endospores form when nutrients are depleted. Which culture would you expect to have more endospores?

A. A 2 day old culture

B. A 5 day old culture

Question #3

A mordant is a compound that binds to a dye to fix it to the substance, in our case, the cell. What acts as the mordant in the Gram stain?

A. Ethanol

B. Iodine

C. Crystal violet

D. Safranin

E. Water

Question #4

In the Gram stain, after washing with Gram's alcohol (95% ethanol), Gram - cells will be

A. pinkish red

B. purple/violet

C. colorless