Question

Two students are working together to Gram stain a mix of Gram positive and Gram negative cells. One of the students accidentally uses a bottle of water instead of ethanol during the decolorization step. How would this mistake alter their results?
A. Gram positive cells would appear pink and Gram negative cells would appear purple.
B. Gram positive cells would appear purple and Gram negative cells would appear pink.
C. Both Gram positive and Gram negative cells would appear purple.
D. Both Gram positive and Gram negative cells would appear pink.

Answer 1

Answer:

C.Both Gram positive and Gram negative cells would appear purple.

Explanation:

Gram staining is a technique used to differentiate bacteria to two main groups based on their difference in cell wall components.

Crystal violet, decolorizer(ethanol) and a counter stain are used.

Gram positive bacteria have a thicker peptidoglycan layer hence they will retain the crystal Violet stain even after decolorization. They will stain purple

Gram negative will stain pink due to losing the initial stain and taking up the counter stain after decolorization.

Therefore, if water is used instead of ethanol. Both bacteria will retain crystal violet stain in their cell wall.