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RE: Where would I ask this question?

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]On Behalf Of
> Dora Smith
> This question is off topic here, but I am wondering if there is a list where
> they consider such matters.
> I want to know if all currently existing life forms on earth have
> mitochondria, or only those that metabolize oxygen for energy?    For
> instance, do bacteria that metabolize sulfur or rock have mitochondria?
Do a web search on "endosymbiosis".

Mitochondria are by no means found in all life, nor even in all eukaryotes. 
They are limited to most eukaryotes, including all the
multicellular forms (plants, animals, fungi, and various multicellular algae). 
See http://www.tolweb.org/Eukaryotes/3 and especially

Mitochondria are themselves the descendants of once free-living 
alpha-proteobacteria. Genomically, their closest known living
relatives are the species of _Rickettsia_, the bacterium that causes the 
diseases spotted fever and typhus!

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796