Mitochondria are organelles that produce energy through oxidative phosphorylation, regulate metabolic activity, and promote cell growth and multiplication.A large number of mitochondria in a cell indicates that the cell has a high energy demand. Some different cells have different amounts of mitochondria because they need more energy. So for example, the muscle has a lot of mitochondria, the liver does too, the kidney as well, and to a certain extent, the brain, which lives off of the energy those mitochondria produce.

A large number of mitochondria in a cell indicates that the cell is active because it has a high demand for energy