Mitochondria organization

Three further volumes of the well-known series Methods in Enzymology deal with the following aspects of biomembranes Biological Oxidations — Specialized techniques Bioenergetics — Oxidative phosphorylation and Bioenergetics — Biogenesis of mitochondria, organization, and transport. ... 

Mitochondria organize electron transfer and the associated reactions leading to the adenosine triphosphate synthesis called oxidative phosphorylation. Synthesis of adenosine triphosphate is an endothermic reaction, and hence conserves the energy released during biological oxidation-reduction reactions. Electron transfer and associated reactions leading to ATP synthesis are membrane-bound phenomena. NADH and FADH2 are the reduced cofactors of NAD" " and the FAD. The oxidation of one NADH produces approximately three... 

Figure 7.8 Comparison of oxygen transport from lung to a cell and then into a mitochondrion with fatty acid transport from an adipocyte to a cell and then into the mitochondria in various tissues/ organs. Fatty add is transported in blood bound to albumin, oxygen is transported in blood bound to haemoglobin. Fatly add is transported within the cell attached to the fatty acid-binding protein (BP), oxygen is transported within a cell attached to myoglobin (Mb). Alb represents albumin, Hb haemoglobin.

The organization of the IM of the C. parvum mitochondrion-related organelle is quite distinct from other amitochondriate protists. With the exception of... 

Eukaryotic cells also have organelles, mitochondria (Fig. 24-6) and chloroplasts, that contain DNA. Mitochondrial DNA (mtDNA) molecules are much smaller than the nuclear chromosomes. In animal cells, mtDNA contains fewer than 20,000 bp (16,569 bp in human mtDNA) and is a circular duplex. Each mitochondrion typically has two to ten copies of this mtDNA molecule, and the number can rise to hundreds in certain cells when an embryo is undergoing cell differentiation. In a few organisms (trypanosomes, for example) each mitochondrion contains thousands of copies of mtDNA, organized into a complex and interlinked matrix known as a kinetoplast. Plant cell mtDNA ranges in size from... 

Mitochondria are present in all eukaryotic cells that use oxygen in respiration, but the number per cell and the form and size vary.1-4 Certain tiny trypanosomes have just one mitochondrion but some oocytes have as many as 3 x 105. Mammalian cells typically contain several hundred mitochondria and liver cells5 more than 1000. Mammalian sperm cells may contain 50-75 mitochondria,6 but in some organisms only one very large helical mitochondrion, formed by the fusion of many individual mitochondria, wraps around the base of the tail. Typical mitochondria appear to be about the size of cells of E. coli. However, study of ultrathin serial sections of a single yeast cell by electron microscopy has shown that, under some growth conditions, all of the mitochondria are interconnected.7... 

Baker s yeast contains at least four lactate dehydrogenases, three of which are located in the mitochondrion and one in the cytoplasm (Table 1). Electron flow in the mitochondrial enzymes is linked to cytochromes rather than nicotinamides. Their apparent physiological function is the reversible interconversion of pyruvate and lactate, and it is not clear whether any of these four enzymes accept ketones other than pyruvate, which would limit their importance in organic synthesis. 

MITOCHONDRION A membrane-bound organelle of eukaryotic organisms that replicates independently of the cell nucleus and contains its own ENA and its own protein-synthesizing apparatus its function is to provide energy to the cell in the form of adenosine triphosphate by oxidative phosphorylation. 

The title of this book means that our inquiry about metabolism must be limited to the actual energy conversion process itself, and it has been widely agreed that this occurs at the mitochondrion in each of the cells of the organism. It is also agreed that the distribution of energy (the currency in respect to wealth) is done by ATP, which yields energy locally when needed. 

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