Cristae of mitochondria

Creutzfeldt-Jakob disease 248 Crick, Francis H. C. 84, 200 Cristae of mitochondria 14 Crossing-over 18 Crosslinking 79 Crotonase. See Enoyl hydratase Crowfoot Hodgkin, Dorothy M. 84 Cruciform structure in nucleic acids 229 Crustacea 24 Cruzain 619 Cryoenzymology 469 elastase 616 Cryoprotectants 191 Crystallins 169 Crystallography 131-137 electron 131 X-ray 132-137 Crystals, liquid 392-394 Crystal systems 133 Cubic symmetry... 

The lattice-like membrane arrangement of the cristae of mitochondria in the giant amoeba was interpreted by Pappas and Brandt [22] to be composed of membranous tubules. If instead of discrete tubules, a continuous surface is assigned in such a way that it links the sections, a cubic membrane can be... 

As further tissues were examined it became evident that the details of mitochondrial morphology were very variable. While most cells had rod-or sausage-shaped organelles, some were spherical. Other cells had mitochondria with spiral cristae or with massive crystalline inclusions. In confirmation of earlier suggestions from classical microscopists the position of mitochondria in cells was also seen to be linked with the site in the cell where energy was required. In skeletal muscle the mitochondria were adjacent to the myofibrils in the renal tubules they were close to the inner (non-luminal) surface of the cell which was then found to be the location of the Na/K-ATPase involved in active... 

The most typical ultrastructural changes in hepatocytes were sharp swelling of mitochondria with pronounced enlightenment of their matrix and reduction of cristae that are important morphological symptoms of their damage (Fig. 22.2). They were accompanied by appearance of mitochondria of odd shapes, horseshoe shaped... 

Nasirudeen AM, Tan KS (2004) Isolation and characterization of the mitochondrion-like organelle from Blastocystis hominis.J Microbiol Methods 58 101-109 Painter HJ, Morrisey JM, Mather MW, Vaidya AB (2007) Specific role of mitochondrial electron transport in blood-stage Plasmodium falciparum. Nature 446 88-91 Perkins GA, Song JY, Tarsa L, Deerinck TJ, Ellisman MH, Frey TG (1998) Electron tomography of mitochondria from brown adipocytes reveals crista junctions. J Bioeneerg Biomembr 30 431-432... 

FIGURE 19-1 Biochemical anatomy of a mitochondrion. The convolutions (cristae) of the inner membrane provide a very large surface area. The inner membrane of a single liver mitochondrion may have more than 10,000 sets of electron-transfer systems (respiratory chains) and ATP synthase molecules, distributed over the membrane surface. Heart mitochondria, which have more profuse cristae and thus a much larger area of inner membrane, contain more than three times as many sets of electron-transfer systems as liver mitochondria. The mitochondrial pool of coenzymes and intermediates is functionally separate from the cytosolic pool. The mitochondria of invertebrates, plants, and microbial eukaryotes are similar to those shown here, but with much variation in size, shape, and degree of convolution of the inner membrane. 

In eukaryotic cells, electron transport and oxidative phosphorylation occur in mitochondria. Mitochondria have both an outer membrane and an inner membrane with extensive infoldings called cristae (fig. 14.2). The inner membrane separates the internal matrix space from the intermembrane space between the inner and outer membranes. The outer membrane has only a few known enzymatic activities and is permeable to molecules with molecular weights up to about 5,000. By contrast, the inner membrane is impermeable to most ions and polar molecules, and its proteins include the enzymes that catalyze oxygen consumption and formation of ATP. The role of mitochondria in 02 uptake, or respiration, was demonstrated in 1913 by Otto Warburg but was not fully confirmed until 1948, when Eugene Kennedy and Albert Lehninger showed that mitochondria carry out the reactions of the TCA cycle, the transport of electrons to 02, and the formation of ATP. 

Cristae Tightly folded inner membranes of mitochondria where ATP is made. 

Processes occurring inside the mitochondrial matrix include pyruvate oxidation, fatty acid oxidation, amino acid metabolism, and the citric acid cycle. Furthermore, respiratory proteins are bound to the inner membrane, so the density of cristae corresponds to the respiratory activity of a cell. For example, mitochondria in heart muscle cells (high rates of respiration) are densely packed with cristae, whereas mitochondria in liver cells (low rates of respiration) have more sparsely distributed cristae. 

Thin section of mitochondria showing closely spaced cristae. Courtesy of Kenneth Moore, University of Iowa. 

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