Distinguish endotoxins and exotoxins with examples.

Study for the Cengage Microbiology Test with helpful multiple choice questions and detailed explanations. Ace your exam with confidence!

Distinguishing endotoxins from exotoxins is about their origin and what they are. Endotoxins are components of the outer membrane of Gram-negative bacteria, specifically the lipopolysaccharide (LPS) complex, and they are released when the bacteria lyse. They tend to provoke strong inflammatory responses and fever and are relatively heat-stable. Exotoxins are secreted proteins produced by bacteria into the surrounding environment; they can target specific host processes, with well-known examples like botulinum toxin (a neurotoxin) and cholera toxin (an enterotoxin) that disrupts intestinal function. Because exotoxins are proteins, they are usually more heat-labile and can often be neutralized by specific antibodies, whereas endotoxins are not secreted proteins and persist until cell lysis. The other descriptions misstate either what endotoxins or exotoxins are or where they come from, which is why they don’t fit as accurate distinctions.