What is the primary role of the mitochondria in a cell?

The primary role of mitochondria in a cell is energy production. Mitochondria are often referred to as the "powerhouses" of the cell because they are responsible for generating adenosine triphosphate (ATP), which is the main energy carrier in cells. This process takes place through cellular respiration, where glucose and oxygen are converted into ATP, water, and carbon dioxide.

Mitochondria are equipped with their own DNA and ribosomes, allowing them to produce some of the proteins necessary for their function, but their main contribution to cellular processes is energy production. In contrast, other processes mentioned in the options, such as photosynthesis and protein synthesis, are carried out by different organelles, like chloroplasts in plants for photosynthesis and ribosomes for protein synthesis. The storage of DNA occurs in the cell nucleus, not in the mitochondria, although mitochondrial DNA plays a role in cellular function. Therefore, the correct answer highlights the fundamental role of mitochondria in providing the energy essential for various cellular activities.