From two perspectives; within the domain of Eukaryotic life, is there a most fundamental chemical compound, and in a broader sense, the most fundamental chemical compound in our world. Fundamental being defined as necessary for life/existence.

 

 

 

 

sorry if this is silly sounding

 

 

H₂O ?

From life's perspective, I agree with Ophiolite that it's probably water.

 

From the universe's perspective, it probably has to be hydrogen... but I am undecided whether that should be the H₂ molecule, or hydrogen plasma as found in stars.

I agree it is water. Liquid water (which means the right temperature and a bit of pressure, too).

 

Hydrogen bonds are key to life in the respect that they allow for:

a) specific interactions (without chemical reactions) of already quite small molecules (like base pairing of two RNA segments)

b) separate between two phases in liquids (hydrophil and hydrophob) to form membranes.

 

Besides H₂O, there is only NH₃ and FH which at least theoretically can provide a liquid with hydrogen bond forming capabilities (It does not work with heavier atoms any more and alcohols will not form in sufficient quantity on any planet to form liquid alcohol seas.). F is too rare. Liquid NH₃ is might be too cold for effective biochemical reactions.

you could also say it it the carbon backbone.

all life is built using carbon chains as the backbone to the molecule, its just convenient, stable, and it can make alot of bonds.

 

carbon gives life structure

you could also say it it the carbon backbone.

all life is built using carbon chains as the backbone to the molecule, its just convenient, stable, and it can make alot of bonds.

 

carbon gives life structure

 

I agree.

For the environment of life it is liquid water, for life itself it is carbon with its capability of forming stable chains and other diverse chemical properties.