Mitochondria is a double layer oval shaped organelle. The outer membrane and infolded inner membrane. The folds in the inner membrane of a mitochondrion are called as cristae. It has a characteristic wrinkled shape, providing a large amount of surface area for chemical reactions to occur on. This aids aerobic cellular respiration since the mitochondrion requires oxygen. Cristae are studded with proteins, including ATP synthase and a variety of cytochromes.