Mitochondrial Structure: Two Types of Subunits on Negatively Stained Mitochondrial Membranes

Projecting subunits were seen on the cristae of all 11 types of mitochondria examined by electron microscopy. These consisted of a stem, 30 to 35 A wide and 45 to 50 A long, and a round head 75 to 80 A in diameter. The outer membranes of rat liver mitochondria showed regular arrays of hollow cylindrical subunits 60 A by 60 A.