I heard an exobiologist who said that living organism are made

>>8971328
>>>/gtfo/
take your poorly worded questions with you

>>8971329
English is not my mother tongue. You needn't to so be so rude.

>>8971328
yes, even on earth life can exist without oxygen
>>8971329
you Sir, you suck

One reason carbon is so good is because it can form four covalent bonds with other elements instead of just 2 or 3; this provides a lot of "room" for molecules to grow into useful shapes and configurations.

You should read about what exactly oxygen does for us, namely oxidative phosphorylation. It is a very good electron acceptor, and this affords the electrons donated to the electron transport chain via the oxidation of carbons in sugar a whole lot of potential energy. These electrons are able to do a whole lot of work as they pass from one electron acceptor to the next, more electronegative acceptor (with oxygen being the final thing to be reduced).

Asking whether oxygen is necessary on another planet presupposes the existence of mitochondrial electron transport as it exists on Earth. Quite an assumption.

>>8971331
It's exceedingly rare. The only life I'm aware of that can live sans oxygen are in miles-deep oceanic trenches near volcanic vents.

>>8971344
is this bait?

>>8971348
It isn't. Give some examples?

Ok, a number of organisms can survive in an inactive state in anoxic conditions, e.g. tardigrades and brine shrimp. But what about live and thrive in *active* states? Reproduce?

>>8971361
plants and most bacteria

>>8971365
Plants absolutely need oxygen to survive
http://scienceline.ucsb.edu/getkey.php?key=760

It looks like you're right about at least some bacteria though.

could be silicon and sulphur, rather than
carbon and oxygen, but would require
much different conditions

>>8971331
>yes, even on earth life can exist without oxygen

This is false. All known Earth organisms require oxygen to simply exist. Just break the organism down into its chemistry and you will always find oxygen somewhere.

Don't confuse processing sulphur in deep sea vents as not needing oxygen.