Final answer:
Exotoxins are potent protein molecules secreted by pathogenic bacteria, requiring low doses to cause specific harm through precise targeting, while endotoxins are lipid components of gram-negative bacteria that elicit robust inflammatory responses and commonly induce fever.
Step-by-step explanation:
When contrasting the properties of exotoxins and endotoxins, we find significant differences in their composition, toxicity, and physiological effects. On the one hand, exotoxins are protein molecules synthesized and secreted by living pathogenic bacteria, with many originating from gram-positive bacteria. They are highly potent, requiring minuscule amounts to cause harm, and demonstrate specific targeting, which allows them to bind to certain cell types and interfere with cellular functions. A notable instance is botulinum toxin, with an extremely low lethal dose (LD50).
On the other hand, endotoxins consist of the lipid A portion of lipopolysaccharides (LPS) that are integral to the outer membrane of gram-negative bacteria. These are released upon bacterial cell death or during cell division and can trigger a robust inflammatory response at high concentrations, potentially causing septic shock. They are less toxic on a per-weight basis compared to exotoxins but are potent pyrogens, often leading to fever as a common symptom.
Hemolysins mentioned in statement 4 are indeed examples of exotoxins that disrupt cell membranes, not endotoxins. The production of fever primarily pertains to endotoxins, although certain exotoxins like superantigens can also provoke fever through excessive immune activation, as outlined in statement 5.
Corrected question: Assess the following statements, and select those that correctly apply to the properties of exotoxins and endotoxins.
1.) Exotoxins typically cause systemic effects, whereas endotoxins precisely target a specific tissue type; e.g., neurological tissue.
2.) Exotoxins are made of protein that are synthesized and secreted by a living cell, whereas endotoxins are comprised of lipopolysaccharide found in the outer membrane of gram-negative bacteria.
3.) Endotoxins demonstrate potent toxicity; their lethal dose is low compared to exotoxins, which require a high dose to cause disease manifestations.
4.) Hemolysins are examples of endotoxin. They may exhibit β-hemolysis, complete lysis of erythrocytes; or α-hemolysis, partial lysis which manifests as a greenish tinge on blood agar.
5.) Endotoxin is a pyrogen that routinely causes a fever whereas exotoxins do not usually cause a fever unless TNF production is stimulated as part of the pathogenic effects.