Which structure is involved in the breakdown of excess fatty acids and detoxification in cells?

The peroxisome is the structure that plays a crucial role in the breakdown of excess fatty acids and detoxification within cells. Peroxisomes contain enzymes that are responsible for oxidizing fatty acids, which can be used for energy production or converted into other molecules needed by the cell. They also perform a vital function in detoxifying harmful substances, such as hydrogen peroxide, converting it into water and oxygen with the help of catalase.

The other structures listed do not serve the same specific functions. Lysosomes are primarily involved in the degradation of macromolecules, cellular debris, and pathogens through enzymatic digestion. The rough endoplasmic reticulum is mainly responsible for the synthesis of proteins that are either secreted from the cell or incorporated into membranes. The nucleolus is involved in ribosomal RNA synthesis but does not participate in fatty acid metabolism or detoxification processes. This clarity underscores the essential role of peroxisomes in cellular metabolism and homeostasis.