Advanced Placement (AP) Biology Practice Exam

What is the primary function of peroxisomes in cells?

1. Energy production through respiration

2. Detoxification of harmful substances

3. Storage of genetic information

4. Synthesis of lipids

The correct answer is: Detoxification of harmful substances

Peroxisomes play a crucial role in detoxifying harmful substances within the cell. They contain enzymes that are involved in the breakdown of fatty acids and amino acids, as well as the detoxification of hydrogen peroxide, a byproduct of various metabolic reactions. The enzyme catalase found in peroxisomes converts hydrogen peroxide into water and oxygen, thereby reducing its potential harm to the cell. This detoxifying function is significant for maintaining cellular health, especially in cells that are exposed to high levels of reactive oxygen species or toxic compounds. In contrast, while peroxisomes are involved in lipid metabolism, their primary function is not to synthesize lipids but rather to break down fatty acids. The energy production process primarily occurs in mitochondria, not peroxisomes, and genetic information is stored in the nucleus of the cell. Thus, the emphasis on detoxification distinctively highlights the core role of peroxisomes in cellular function.