Tuesday, April 13, 2010

What is the name of the theory explaining the evolutionary origin of chloroplast and mitochondria?

Who initially proposed the theory and what are the three pieces of evidence that support this theory?

What is the name of the theory explaining the evolutionary origin of chloroplast and mitochondria?
It is the Endosymbiotic Theory.


Originally proposed by the Russian botanist Konstantin Mereschkowski in 1905, but popularised by by Lynn Margulis in her 1981 book "Symbiosis in Cell Evolution"





Evidence for the theory includes:


- Mitochondira and plastids have DNA of their own, distinct from nuclear DNA. It is in the circular form that bacterial DNA takes, and sequence data shows it is in fact closely related to certain types of bacteria.


- while some nuclear genes make proteins for the mitochondria and plastids, they also use their own DNA to make their own proteins. The ribosomes found in the organelles are identical to prokaryotic ribosomes (70s), and distinct from the eukaryotic ribosomes (80s).


- The inner membranes of the mitochondria and plastids are similar in composition to bacterial membranes, and different from the "normal" eukaryotic membrane.


- mitochondria and plastids reproduce by themselves, independently of division of the host cell.
Reply:I'm sure it's in your textbook. Just go to the index and look for something like "mitochondria, origin of, pg#"
Reply:the Endosymbiont Theory


No comments:

Post a Comment