**Core Concept**
The bacterial cell wall is a critical structure that provides shape, protection, and maintains the osmotic balance of the cell. It is composed of various layers, including the peptidoglycan (also known as murein) layer, which is the primary component responsible for the cell wall's rigidity and strength.

**Why the Correct Answer is Right**
The peptidoglycan layer is composed of a network of branched chains of sugars and amino acids, including N-acetylmuramic acid and N-acetylglucosamine. This layer is cross-linked by short peptides, forming a strong and rigid structure that maintains the cell's shape and provides protection against osmotic pressure. The presence of peptidoglycan is a key characteristic of Gram-positive and Gram-negative bacteria.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because teichoic acids are components of the cell wall in Gram-positive bacteria, but they are not a universal component of the bacterial cell wall.
**Option B:** This option is incorrect because lipopolysaccharides (LPS) are components of the outer membrane in Gram-negative bacteria, but they are not a universal component of the bacterial cell wall.
**Option C:** This option is incorrect because porins are proteins that form channels in the outer membrane of Gram-negative bacteria, but they are not a structural component of the bacterial cell wall.

**Clinical Pearl / High-Yield Fact**
The bacterial cell wall plays a crucial role in the pathogenesis of bacterial infections, and its composition can influence the effectiveness of antibiotics. Penicillin, for example, targets the synthesis of peptidoglycan, which is essential for cell wall formation and maintenance.

**Correct Answer:** D.