Pentachlorophenol is used as which types of compounds and how does it induce toxicologic damage?

• A. Fungicide, herbicide, bactericide and wood preservative; uncouples oxidative phosphorylation
• B. Fungicide and insecticide; inhibits acetylcholinesterase
• C. Herbicide and fungicide; inhibits protein synthesis
• D. Fungicide, wood preservative; uncouples oxidative phosphorylation

Answer: (A)

Pentachlorophenol functions as a broad-spectrum pesticide and wood preservative, including fungicidal, herbicidal, and bactericidal uses. Its toxic effect comes from uncoupling oxidative phosphorylation in mitochondria: it collapses the proton gradient across the inner mitochondrial membrane, so ATP production drops while electron transport may continue. This energy shortfall hits tissues with high energy demands, leading to cellular injury and organ toxicity. The other mechanistic options describe effects not characteristic of pentachlorophenol, and some uses are omitted, making the uncoupling mechanism with the broad-spectrum preservative/ pesticide roles the best match.