Mitochondria are where cellular respiration occurs in the cell. The chemical equation for cellular respiration is:
Thus, in the presence of oxygen, cellular respiration releases energy from food (such as glucose, C6H12O6) in order to make carbon dioxide, water and energy in the form of ATP.
Therefore, cellular respiration interacts indirectly with the chloroplast of te cells of autotrophic organisms/producers (those that make their own food via photosynthesis). The equation for photosynthesis is:
As you can see, photosynthesis and cellular respiration are inverses of one another. The products of one question are the reactants to the other. Therefore, the mitochondria and the chloroplasts depend on one another.
Because mitochondria make energy (ATP), the number of mitochondria in a cell is directly proportional to a cell's energy output. For example, a muscle cell has more mitochondria than fat cells.