Mitochondria are producing ROS, and if they produce too much of it, it can damage the mitochondrial DNA or other parts. This can lead to defective mitochondria. When mitochondria are defective, they are supposed to be disposed of and recycled, with new ones taking their place. If this doesn’t happen, a cell can be left with a workforce shortage. It’s well established that the number of mitochondria in our cells decreases as we get older, resulting in less metabolic capacity for cells.
