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A mitochondrion (plural mitochondria; Fig. 1) is a membrane-enclosed organelle. Mitochondria are distributed through the cytosol of most eukaryotic cell|s. Their main function is the conversion of the potential energy (electron transport) of food molecules into ATP (the universal energy currency of the cell). They are composed olds called cristae which give a much increased surface area for chemical reactions to take place on. f: |
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A mitochondrion (plural mitochondria; Fig. 1) is a membrane-enclosed organelle. Mitochondria are distributed through the cytosol of most eukaryotic cells. Their main function is the conversion of the potential energy (electron transport) of food molecules into ATP (the universal energy currency of the cell). They are composed olds called cristae which give a much increased surface area for chemical reactions to take place on. |
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* The intermembrane space between the two membranes contains enzymes that use ATP to phosphorylate? other nucleotides. |
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* The intermembrane space between the two membranes contains enzymes that use ATP to phosphorylate? other nucleotides. |
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Mitochondrion literally means 'thread granule', which is what they look like under a microscope; tiny rod-like structures present in the cytoplasm of all cells. The matrix contains soluble enzymes that catalyze (enable) the respiration? of [pyruvic acid]? and other small organic molecules. Parts of the Krebs Cycle occur in Mitochondria. It also contains several copies of the DNA (5-10 circular DNA molecules per copy) of the mitochondria, as well as special mitochondrial ribosomes, tRNAs and proteins needed for DNA replication. When the cell divides mitochondria replicate by fission. They also replicate if the long-term energy demands of a cell increase. For example fat storage cells, which require little energy, have very few mitochondria, but energy-demanding muscle cells tend to have many. Mitochondria are generally considered to be highly modified symbiotic bacteria, probably belonging to the alpha-proteo bacteria (with the closest known candidate being Rickettsia, the causing agent of typhus?), and are believed to have been incorporated only once (compare chloroplast). |
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Mitochondrion literally means 'thread granule', which is what they look like under a microscope; tiny rod-like structures present in the cytoplasm of all cells. The matrix contains soluble enzymes that catalyze (enable) the respiration? of [pyruvic acid]? and other small organic molecules. Parts of the Krebs Cycle occur in Mitochondria. It also contains several copies of the DNA (5-10 circular DNA molecules per copy) of the mitochondria, as well as special mitochondrial ribosomes, tRNAs and proteins needed for DNA replication. When the cell divides mitochondria replicate by fission. They also replicate if the long-term energy demands of a cell increase. For example fat storage cells, which require little energy, have very few mitochondria, but energy-demanding muscle cells tend to have many. Mitochondria are generally considered to be highly modified symbiotic bacteria, probably belonging to the alpha-proteo bacteria (with the closest known candidate being Rickettsia, the causing agent of typhus?), and are believed to have been incorporated only once (compare chloroplast). |
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The energy from the food molecules (e.g., glucose) was converted to NADH and FADH molecules in glycolysis and the Citric acid cycle. That energy is transferred to oxygen (O2) in several steps. The protein complexes in the inner membrane ([NADH dehydrogenase]?, [Cytochrome C reductase]?, [Cytochrome C oxidase]?) which perform the transfer use the released energy to pump protons (H+) against a gradient (the concentration of protons in the matrix is higher than that in the intermembrane space). An [active transport]? (using energy) is required to pump the protons against their physical tendency (in the "wrong" direction) from the matrix into the intermembrane space. |
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The energy from the food molecules (e.g., glucose) was converted to NADH and FADH molecules in glycolysis and the Citric acid cycle. That energy is transferred to oxygen (O2) in several steps. The protein complexes in the inner membrane ([NADH dehydrogenase]?, Cytochrome C reductase, Cytochrome C oxidase) which perform the transfer use the released energy to pump protons (H+) against a gradient (the concentration of protons in the matrix is higher than that in the intermembrane space). An [active transport]? (using energy) is required to pump the protons against their physical tendency (in the "wrong" direction) from the matrix into the intermembrane space. |
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make ATP from ADP and inorganic phosphate (Pi). This process is called chemiosmosis and is an example of facilitated diffusion. Part of the 1997 Nobel Prize in Chemistry was awarded to [Paul D. Boyer]? and [John E. Walker]? for their discovery of the working mechanism of ATP synthase. |
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make ATP from ADP and inorganic phosphate (Pi). This process is called chemiosmosis and is an example of facilitated diffusion. Part of the 1997 Nobel Prize in Chemistry was awarded to [Paul D. Boyer]? and [John E. Walker]? for their discovery of the working mechanism of ATP synthase. |
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