Mitochondria Mitochondria are responsible for energy production. They are also the responsible location for which respiration takes place. Mitochondria contain enzymes that help convert food material into adenosine triphosphate (ATP), which can be used directly by the cell as an energy source. Mitochondria tend to be concentrated near cellular structures that require large inputs of energy, such as the flagellum. The role of the mitochondria is very important in respiration. In the presence of oxygen, pyruvate or fatty acids, can be further oxidized in the mitochondria. Each mitochondrion is enclosed by two membranes separated by an intermembrane space. The i