Fig. 1
From: Structure and function of mitochondrial membrane protein complexes
Membrane compartments in the mitochondrion. The outer membrane separates mitochondria from the cytoplasm. It surrounds the inner membrane, which separates the inter-membrane space from the protein-dense central matrix. The inner membrane is differentiated into the inner boundary membrane and the cristae. The two regions are continuous at the crista junctions. The cristae extend more or less deeply into the matrix and are the main sites of mitochondrial energy conversion. The shallow proton gradient between the inter-membrane space (pH 7.2–7.4) and the matrix (pH 7.9–8) drives ATP production by the ATP synthase in the membranes of the cristae. (Adapted from Figure 14–8 C in Alberts B. et al. Molecular Biology of the Cell. 6th ed. New York: Garland Science; 2014, with permission of the publisher [© 2015 from Molecular Biology of the Cell, Sixth Edition by Alberts et al. Reproduced by permission of Garland Science/Taylor & Francis Group LLC])