Which component is associated with the outer membrane of Gram-negative bacteria?

The outer membrane of Gram-negative bacteria is characterized by the presence of lipopolysaccharides (LPS), which play a crucial role in the structure and function of this membrane. Endotoxins are components of LPS and are considered an essential feature of the outer membrane. When Gram-negative bacteria are lysed, endotoxins can be released into the surrounding environment, triggering strong immune responses in the host. This biological activity is why endotoxins are often referenced when discussing the pathological impacts of Gram-negative bacterial infections.

In contrast, while protein disulfide isomerase is involved in protein folding in the cell, it is not a component of the outer membrane. Peptidoglycan is primarily associated with the cell wall structure of both Gram-positive and Gram-negative bacteria, but it is located differently in relation to the outer membrane. Cellulose is not a component of bacterial membranes; it is mainly found in plant cell walls. Therefore, the unique association of endotoxins with the outer membrane of Gram-negative bacteria distinguishes it as the correct answer.