* Muscle cells (especially heart muscle): Muscle contraction requires a tremendous amount of ATP, the cell's energy currency, which is produced by mitochondria.
* Brain cells (neurons): Neurons are very active cells that need a lot of energy for transmitting signals.
* Liver cells (hepatocytes): These cells perform many metabolic functions, including detoxification, which requires a lot of energy.
* Kidney cells: These cells are responsible for filtering waste and regulating blood pressure, both processes that require significant energy.
* Sperm cells: Sperm cells need a lot of energy to swim towards the egg.
Fun fact: Mitochondria are often called the "powerhouses of the cell" because they are responsible for producing ATP through cellular respiration.
