Question

Nadia has an infection caused by Streptococcus pyogenes, which has a Gram-positive cell wall. What distinguishes Gram-positive bacterial cell walls from Gram-negative bacteria cell walls?

a) Presence of lipopolysaccharide
b) Thickness of peptidoglycan layer
c) Presence of an outer membrane
d) Lack of teichoic acids

Answer 1

Gram-positive bacterial cell walls like that of Streptococcus pyogenes are distinguished by a thicker peptidoglycan layer and lack an outer membrane, which is present in Gram-negative bacteria.

Step-by-step explanation:

Nadia's infection by Streptococcus pyogenes, a Gram-positive bacterium, involves a cell wall structurally distinct from that of Gram-negative bacteria. One key difference is the thickness of the peptidoglycan layer, which is much thicker in Gram-positive bacteria. Additionally, Gram-positive bacteria cell walls typically lack the outer membrane found in Gram-negative bacteria. Instead, their walls contain teichoic acids, which may form lipoteichoic acids that anchor the cell wall to the cell membrane. Conversely, Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane that includes lipopolysaccharides (LPS) and lipoproteins.