A peroxisome is a membrane-bound organelle, a type of microbody, found in the cytoplasm of virtually all eukaryotic cells. It houses enzymes involved in oxidation reactions, which produce hydrogen peroxide () as a by-product. The enzymes break down fatty acids and fatty acids, and they also detoxify some substances that enter the body. For example, alcohol is detoxified by peroxisomes found in liver cells.
Importantly, peroxisomes—unlike lysosomes—are not part of the endomembrane system. That means they don’t receive vesicles from the Golgi apparatus.