What differentiates gram-positive bacteria from gram-negative bacteria?
A) The appearance of colonies
B) Nutrient requirements
C) The way the cell wall stains
D) The use of oxygen
E) The means of locomotion

Question

Quizplus · Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer in their cell wall that retains the crystal violet stain used in the Gram staining procedure, making them appear purple under a microscope. In contrast, gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane that does not retain the crystal violet stain but takes up the counterstain (usually safranin), appearing pink or red. This difference in cell wall composition and staining response is what differentiates gram-positive from gram-negative bacteria.

What Differentiates Gram-Positive Bacteria from Gram-Negative Bacteria