Final answer:
Living pathogenic bacteria may harm their human hosts by releasing toxic waste products called endotoxins or exotoxins.
Step-by-step explanation:
Living pathogenic bacteria may harm their human hosts by releasing toxic waste products called endotoxins or exotoxins. Endotoxins are the lipid A component of the lipopolysaccharide (LPS) found on the outer membrane of gram-negative bacteria. Exotoxins, on the other hand, are proteins secreted mainly by gram-positive bacteria but can also be secreted by gram-negative bacteria. Unlike endotoxins, exotoxins are much more specific in their actions, targeting specific receptors on specific cells and damaging those cells through unique molecular mechanisms.