According to About.com, cellular respiration takes place in the mitochondria. While mitochondria primarily exist to serve as “power plants” for the cell, converting natural resources into usable energy, they also play a role in cellular division, cell growth and cell death.
About.com explains that mitochondria are surrounded by a double-layer of phospholipids and embedded proteins. Mitochondria are pill-shaped, and their internal structure features two key parts. The intermembrane space resides between the double-layered membrane, while the other part forms the inner mitochondrial matrix. The matrix features inward-facing projections called cristae, which enhance the productivity of the mitochondria by increasing the amount of surface area available for cellular respiration to take place. Many enzymes that are crucial to the process of cellular respiration are found in the mitochondria.
Mitochondria are semi-independent organelles which reproduce by fission, according to About.com. In addition to containing their own DNA, mitochondria have their own ribosomes, which allow them to construct the proteins they need. Rice University explains that these features led scientists in the 1970s to hypothesize that mitochondria have an extracellular origin, and they may be “captured” bacterial cells. The chloroplasts of plants serve a parallel function and may also have an extracellular origin.