The mitochondrion is the powerhouse of the cell. It is the site of respiration. It has a double membrane. From this view you can see very little; first cut the outer membrane to get a better look. With the outer membrane removed it is much easier to see the contents of the mitochondrion. The white folded structure is the inner membrane. Most of aerobic respiration occurs along this membrane Get a really good look by cutting the inner membrane. The inner membranes is ruffled. It has a very large surface area. These ruffles are called cristae. Mitochondria have their own DNA and manufacture some their own proteins. It is thought that the mitochondrion evolved from symbiotic bacteria that took up residence inside the first eukaryotic cells.