Date: October 24, 2014
Source: Scientific American
http://blogs.scientificamerican.com/life-unbounded/2014/10/24/complex-life-owes-its-existence-to-parasites/
The current theory as to how mitochondria developed in our cells is that a very long time ago, by some stroke of luck, a prokaryotic organisms merged together and developed into our complex cells. However, new research suggests a different theory may have occurred, where instead of two cells merging, the first mitochondria was a parasite. So a bacterium whose intention was to steal energy from the cell, ended up providing the energy for the cell. This is supported by research at the University of Virginia, where researchers studied the genetic relationships shared by mitochondria and different types of bacteria. Researchers tried to reconstruct the metabolic processes of the earliest mitochondria and their predecessors, and found that they were most likely to be mobile chemical energy parasites. This argument would make a lot of sense for parasites are found everywhere throughout nature, it can even be argued that Earth is dominated by parasites.
This article directly relates to our curriculum on two fronts, symbiotic relationships and the origin of life. During our ecology unit, we discussed symbiotic relationships, parasitism in particular, which is the relationship where one organism benefits and one is harmed, or in this case the other organism eventually benefits. In our current unit, cells, we recently discussed the origins of life and mitochondria, and we discussed the current theory, that prokaryotic bacteria merged into cells and developed into mitochondria, but not the theory put forth here.
It seems like a big leap from a parasite that steals its host's energy to a vital part of a cell which is the main producer of energy within a cell. What kind of intermediate steps did the mitochondria have to take to have it end up effectively switching its biological role?
ReplyDeleteIt enters as a parasite that lives within the host cell, an endosymbiont, a cell living within another cell. The parasites ability to create energy benefits the host and eventually assimilates into the cell and becomes a mitochondrion. It remains a theory as not all the information is there yet.
DeleteMitochondria are now described as the cell's powerhouse, so how did eukaryotic cells function and obtain energy before this symbiotic relationship was formed?
ReplyDeleteWell before mitochondria were developed, chances are the cell was prokaryotic not eukaryotic and would have gotten its energy the same way prokaryotic cells do today, glycolysis which turns glucose into a molecule called pyruvate which is then converted into energy.
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