Mitochondria
The mitochondria's main role in the cell is to take glucose and use the energy they stored in its chemical bonds to make ATP in a process called cellular respiration. There are 3 main steps to this process: glycolysis, the citric acid cycle or Krebs cycle, and ATP Synthesis. This ATP is released from the mitochondrion, and broken down by the other organelles of the cell to power their own functions.