What role do mitochondria play in a cell?

Mitochondria are often referred to as the powerhouse of the cell, primarily because their main function is to produce adenosine triphosphate (ATP) through the process of aerobic respiration. During this process, mitochondria convert the energy stored in glucose and other organic molecules into ATP, which serves as the primary energy currency for cellular activities. The production of ATP is critical for various cell functions, including metabolism, growth, and movement.

In addition to ATP production, mitochondria are also involved in various metabolic processes and play a key role in regulating cellular respiration, the citric acid cycle, and energy metabolism. They contain their own DNA and ribosomes, highlighting their endosymbiotic origin, but their primary contribution is to energy production, making option B the correct choice in this context.