Final answer:
The distinction among effector, exotoxin, and endotoxin is that effectors are structurally integral units that trigger a response, exotoxins are potent, secreted protein toxins with specific target sites, and endotoxins are structural components causing general inflammatory responses.
Step-by-step explanation:
The correct answer to the question regarding the difference between an effector, an exotoxin, and an endotoxin is option B) Structural toxin, Cellular response, Secreted toxin. The term "effector" generally refers to cells that have a direct effect, such as producing a response in immune function; in this context, it is about the structure or unit facilitating a response. An exotoxin is a type of protein molecule secreted by bacteria, often gram-positive, which has a very specific and potent effect on host cells, such as disabling specific cellular functions. By contrast, endotoxin refers to a component (lipid A) of the outer membrane of gram-negative bacteria, which, when released, can cause a systemic inflammatory response in a host organism.
Endotoxins are notably more heat-stable, while exotoxins tend to be heat-labile due to their protein structure. An example of an exotoxin is the botulinum toxin, which has a significant impact, even in very small concentrations, proving to be much more lethal than endotoxins. Of the three classes of exotoxins, they can be classified as intracellular targeting, membrane disrupting, or superantigens, all differing in their mechanisms of interaction with the host cells.