My favorite part of the cell is the mitochondria. This is where all the energy used in the cell comes from, it is the powerhouse of the cell. Mitochondria are one of the most important parts of the cell, they generate energy, which is ATP (adenosine triphosphate), through a process called cellular respiration. The energy spreads throughout the cell, and all the organelles are powered up. Without the mitochondria, the cell would shut down. And when cells shut down, so do we. Overall, without the mitochondria, the cell would not work properly.