Here's why:

* Cellular Respiration: Mitochondria are the powerhouses of the cell, responsible for cellular respiration. This process breaks down glucose (sugar) and converts it into ATP (adenosine triphosphate), which is the cell's primary energy currency.

* ATP Production: ATP is used for various cellular processes, including muscle contraction, nerve impulse transmission, protein synthesis, and maintaining cell structure.

Let me know if you'd like to learn more about mitochondria or cellular respiration!