What is the main function of mitochondria in cells?

Mitochondria are often referred to as the powerhouse of the cell due to their critical role in energy production. Their primary function is to facilitate cellular respiration, a process in which they convert biochemical energy from nutrients into adenosine triphosphate (ATP), the energy currency of the cell. This conversion primarily occurs through oxidative phosphorylation and the Krebs cycle, allowing cells to efficiently harness energy from carbohydrates, fats, and proteins.

The energy generated by mitochondria is essential for numerous cellular processes, including metabolism, muscle contraction, and biosynthesis. Without adequate mitochondrial function, cells would struggle to meet their energy demands, leading to compromised cellular activities and overall dysfunction. Thus, the production of energy through cellular respiration is the defining characteristic of mitochondria, making this option the correct answer.