The organelle that doses this is called the mitochondrion. Mitochondria are the "energy powerhouses" of animal cells. They are responsible for energy production to meet the needs of the cell as it carries out it's life processes. The mitochondrion does this by taking a glucose molecule and reacting it with an oxygen molecule. This process is known as cellular respiration. The mitochondrion produces energy in the form of ATP (adenosine triphosphate), along with carbon dioxide and water, as waste products.
The number of mitochondria in a cell is directly proportional to the cell's energy requirements. For example, adipose cells (fat cells) have little energy requirements, since they are used for fat storage. Heart cells (cardiac cells), on the other hand, have energy needs all day, every day, so they have mitochondria by the thousands. And it's a good thing, too; if your heart ever runs out of energy, your life is over!
Mitochondrion (plural mitochondria) supply energy to the cell. They are the siteof respiration.
Cells with many mitochondrion (examples, muscles and liver in animals, meristems in plants) produce lots of energy. Cells with few mitochondria produce less energy.
It is on the inner membranes, especially the infoldings, that energy is released. If more infoldings are present they will cause the mitochondria to produce more energy.
Each mitochondion has its own loop of DNA.