What type of bacterial toxin tends to be secreted and has specific cellular targets?

The correct answer is associated with a type of toxin known as exotoxin. Exotoxins are proteins secreted by bacteria into their surroundings, and they have specific cellular targets, allowing them to disrupt various biological processes. For example, some exotoxins can interfere with protein synthesis, activate signaling pathways, or damage cell membranes, leading to cellular dysfunction.

In contrast, endotoxins are components of the bacterial cell wall, specifically lipopolysaccharides (LPS), found in Gram-negative bacteria. They are not secreted but released upon cell lysis and generally impart a more systemic effect, leading to inflammatory responses rather than direct cellular targeting.

Peptidoglycan is a structural component of the bacterial cell wall that provides rigidity and shape but does not function as a toxin. Nucleic acids, while critical for genetic material in all organisms, do not serve as toxins and do not have the same pathogenic roles as exotoxins.

Thus, exotoxins are defined by their ability to be secreted by bacteria and their targeted actions on specific cells, making them a significant factor in the pathogenesis of many bacterial infections.