Question

exam content
page 31 of 50
question 31
mycobacterium and nocardia are different from most gram - positive bacteria in that their cell walls
a are easily decolorized during staining
b contain a layer of lipopolysaccharide
c contain more peptidoglycan
d contain unique, waxy lipids

Explanation:

Mycobacterium and Nocardia have cell - walls with unique, waxy lipids (mycolic acids). This is a distinguishing feature from most gram - positive bacteria. They are acid - fast bacteria due to these lipids. Lipopolysaccharide is typical of gram - negative bacteria. Gram - positive bacteria usually have more peptidoglycan than these two genera. And they are not easily decolorized during staining because of the waxy lipid layer.

Answer:

D. contain unique, waxy lipids