Which description best characterizes the cell wall of a Gram-positive bacterium?

• A. A thick layer of peptidoglycan containing teichoic acids
• B. A thin peptidoglycan layer surrounded by an outer membrane
• C. Contains lipopolysaccharide and a thin peptidoglycan layer
• D. Lacks peptidoglycan and is composed mainly of proteins

Answer: (A)

Verified step by step guidance

1. Recall the fundamental structural differences between Gram-positive and Gram-negative bacterial cell walls. Gram-positive bacteria have a distinct cell wall composition compared to Gram-negative bacteria.
2. Understand that Gram-positive bacteria have a thick peptidoglycan layer, which provides rigidity and shape to the cell. This layer is much thicker than in Gram-negative bacteria.
3. Recognize that Gram-positive cell walls contain teichoic acids, which are polymers of glycerol or ribitol phosphate. These acids are embedded within the thick peptidoglycan layer and play roles in cell wall maintenance and ion regulation.
4. Contrast this with Gram-negative bacteria, which have a thin peptidoglycan layer located between the inner cytoplasmic membrane and an outer membrane containing lipopolysaccharides (LPS).
5. Conclude that the best description of a Gram-positive bacterial cell wall is a thick layer of peptidoglycan containing teichoic acids, distinguishing it from the other options that describe Gram-negative or atypical cell walls.