Final answer:
Penicillin is an example of an irreversible inhibitor which permanently binds to enzymes required for bacterial cell wall formation, making it distinct from reversible, competitive, and noncompetitive inhibitors.
Step-by-step explanation:
An example of an irreversible inhibitor is penicillin. Penicillin works by covalently binding to the enzymes that bacteria need to form their cell walls, thereby permanently inhibiting enzyme function and leading to the destruction of the bacteria.
Irreversible inhibitors, such as penicillin, are distinct from reversible inhibitors which bind non-covalently. Unlike competitive inhibitors, which compete with the substrate for the enzyme's active site, or noncompetitive inhibitors, which bind at a different site than the substrate, irreversible inhibitors form covalent bonds that permanently inactivate the enzyme.