The accepted (??) wisdom is that a proteobacterium became an
endosymbiont of an early eukaryote and this led to the present day
system. The timing for this event has been suggested to have occurred
after the splitting of some organisms (ie Giardia) from the rest of the
eukaryotes (Giardia lacks mitochondria).
What did these early eukaryotes do for energy??
We have some examples of eukaryotes (eg. T. vaginalis) that do not have
mitochondria, but clearly their ancestors HAD mitochondria (sequence
similarities of chromosomally-encoded genes to bacterial counterparts
How did pre-mitochondrial eukaryotes break down complex molecules into
CO2 and H2O?
Are there eukaryotic mechanisms (not mitochondrially-encoded) that
facilitate such processes?
Note 1: It's years since I took biochemistry classes!!
Note 2: I hope this msg fits into this newsgroup, I think maybe it does.
Dr. James O. McInerney Ph.D. Phone/Voicemail: +44 171 938 9247
Senior Scientific Officer, email:j.mcinerney at nhm.ac.uk
The Natural History Museum,
London SW7 5BD