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Mitochondrial biogenesis is the process by which cells increase mitochondrial numbers. [ 1 ] [ 2 ] It was first described by John Holloszy in the 1960s, when it was discovered that physical endurance training induced higher mitochondrial content levels, leading to greater glucose uptake by muscles. [ 3 ]
The human mitochondrial genome is the entirety of hereditary information contained in human mitochondria. Mitochondria are small structures in cells that generate energy for the cell to use, and are hence referred to as the "powerhouses" of the cell. Mitochondrial DNA (mtDNA) is not transmitted through nuclear DNA (nDNA).
PGC-1α provides a direct link between external physiological stimuli and the regulation of mitochondrial biogenesis, and is a major factor causing slow-twitch rather than fast-twitch muscle fiber types. [10] Endurance exercise has been shown to activate the PGC-1α gene in human skeletal muscle. [11]
MT-ND1 is located in mitochondrial DNA from base pair 3,307 to 4,262. [5] The MT-ND1 gene produces a 36 kDa protein composed of 318 amino acids. [10] [11] MT-ND1 is one of seven mitochondrial genes encoding subunits of the enzyme NADH dehydrogenase (ubiquinone), together with MT-ND2, MT-ND3, MT-ND4, MT-ND4L, MT-ND5, and MT-ND6.
This means that mitochondrial DNA disorders may occur spontaneously and relatively often. Defects in enzymes that control mitochondrial DNA replication (all of which are encoded for by genes in the nuclear DNA) may also cause mitochondrial DNA mutations. Most mitochondrial function and biogenesis is controlled by nuclear DNA.
Tim9 and Tim10 make up the group of essential small Tim proteins that assist in transport of hydrophobic precursors across the intermembrane space in mammalian cells. Both Tim9 and Tim10 form a hexamer, the Tim9-Tim10 complex, that when associated, functions as a chaperone to assist translocation of preproteins from the outer mitochondrial membrane to the translocase of the inner membrane.
In the early morning hours of Dec. 26, 1996, Patsy Ramsey called 911 to report her 6-year-old daughter JonBenét missing, and found a rambling ransom note left inside their Boulder, Colorado, home.
Mitochondria and plastids contain their own ribosomes; these are more similar to those of bacteria (70S) than those of eukaryotes. [74] Proteins created by mitochondria and chloroplasts use N-formylmethionine as the initiating amino acid, as do proteins created by bacteria but not proteins created by eukaryotic nuclear genes or archaea. [75] [76]