The mitochondria inside a cell produces ATP, or adenosine triphosphate. Cellular respiration is responsible for ATP production, a process in which ATP production occurs after biochemical energy from nutrients is converted.
The mitochondria, also called the powerhouse of a cell, is present in large numbers in almost every cell in the body. How many mitochondria a cell requires ultimately depends on the cell's job. For example, a muscle cell requires a lot of energy, so many mitochondria are necessary, but cells that send out nerve impulses only require a few cells to get the job done. This structure makes energy for cells by taking nutrients and breaking them down. Almost all of the cellular respiration chemical reactions occur within the mitochondria.