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Introduction/training [organization
of the study]
[polarography]
[calibrating]
[research
paper]
Mitochondria theory:
[overview]
[structure]
[Krebs
reactions]
[electron
transport] [the
gradient] [oxidative
phosphorylation]
Mitochondria in vitro: [preparation]
[fate of
substrates] [state
IV] [state
III] [metabolic
poisons] [mitotraces]
[rationale]
[experiments]
Additional topics: [glossary
of terms ] [Hans
Krebs] [origin
of mitochondria] [other
functions]
"Other" Mitochondria FunctionsRole of mitochondria in processes other than oxidative phosphorylationAmong other processes, mitochondria contain their own independent machinery for protein synthesis, including DNA, messenger and transfer RNAs, and ribosomes. They reproduce by fission in a manner similar to that of bacterial cells. In fact, the seeming independence of mitochondria from the eukaryotic cell's genetic code, as well as the resemblance of mitochondria-associated macromolecules to those of bacteria, are strong evidence for an endosymbiotic origin for the organelles.Mitochondrial membranes contain numerous transport systems for the import of metabolites and high energy intermediates, export of ATP which is utilized in the cytosol, and inorganic phosphate, which is returned to the matrix via a phosphate-proton symport that is driven by the chemiosmotic gradient. Thus some of the gradient energy is always used for purposes other than synthesis of ATP. Mitochondria are exceedingly important as storage tanks for calcium ions. Calcium ion concentration is an important second messenger in cells. It must be precisely controlled in various intracellular compartments, or cellular function is compromised. Indeed, calcium itself is a mediator of many toxins. Mitochondria may act as 'sinks' to buffer the effects of calcium overload. |
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Created by David R. Caprette (caprette@rice.edu), Rice University 24 Apr 96
Updated 26 May 05