One difference between gram-positive and gram-negative bacteria is that
A) gram-positive bacteria have more peptidoglycan in their cell walls.
B) gram-positive bacteria have fimbriae but gram-negative bacteria do not.
C) gram-positive bacteria are spiral-shaped, and gram-negative bacteria are either rod-shaped or spherical.
D) only gram-negative bacteria can form endospores.

Question

Quizplus · Accepted Answer

Gram-positive bacteria have a thicker layer of peptidoglycan in their cell walls, which is why they appear purple when stained with crystal violet in the Gram stain procedure. Gram-negative bacteria have a thinner peptidoglycan layer in addition to an outer membrane, which is why they appear red/pink when counterstained with safranin.

B, C, and D are incorrect choices as they do not accurately distinguish between gram-positive and gram-negative bacteria.

One Difference Between Gram-Positive and Gram-Negative Bacteria Is That