Figure 218 from Chapter 7 (Mitochondria) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. The typical structural organization of mitochondria is revealed in this longitudinal section of a mitochondrion and surrounding cytoplasm from pancreas of the bat, Myotis lucifugus. It is bounded by a smooth outer membrane about 7nm thick. An inner membrane has infoldings called cristae that project into the interior of the organelle. Image by Keith Porter. A PDF copy of the accompanying chapter is available on the ASCB’s BioEDUCATE website.