In mitochondria, the outer membrane is semi permeable, and thus resembles a sieve permeable to all molecules of 10,000 Daltons. The inner membrane is selectively permeable and highly convoluted, forming a series of infoldings known as cristae. The enzymes of the electron transport chain are found in the inner membrane, while the outer membrane contains enzymes involved in mitochondrial lipid synthesis. Related Theory The inner membrane surrounds a central fluid-filled space called inner chamber or mitochondrial matrix. The machinery for energy generation can be found on the cristae (infoldings of the inner membrane). The matrix side of the inner membrane and cristae bear numerous tennis racket-like particles called oxysomes or elementary particles or F0−F1 particles. The cristae and the proteins of the inner membrane aid in the production of ATP molecules during oxidative phosphorylation. Enzymes of electron transport chain are located in the inner membrane.