A hepatocyte toxin that targets the organelle involved in drug detoxification would primarily affect which organelle?

• A. Golgi apparatus
• B. Mitochondria
• C. Rough endoplasmic reticulum
• D. Smooth endoplasmic reticulum

Answer: (D)

In liver cells, drug detoxification is carried out mainly by the smooth endoplasmic reticulum, which houses the cytochrome P450 enzymes responsible for phase I oxidation of xenobiotics, followed by phase II conjugation. A toxin that targets the organelle involved in detox would therefore primarily affect the smooth endoplasmic reticulum, impairing the cell’s ability to metabolize and neutralize drugs.

The smooth ER differs from the rough ER, which is studded with ribosomes and focuses on protein synthesis, and from mitochondria, which generate energy and play roles in apoptosis and metabolism but are not specialized for drug detoxification. The Golgi apparatus further processes and packages proteins after synthesis, not directly handling the initial detox steps.