Oxygen Atoms in the Body

[waywardtigerlily]

I am new at Biology and I have an Extra Credit assignment.

When you breathe, where does the oxygen atoms form the oxygen gas ultimately go? Please do a detailed Mass Balance of the ultimate fate of the oxygen through all of its physiology paths. Be as detailed and specific as you can, and do not leave out or miss the important and obvious ones.

I talked to the teacher and all he would tell me is...there is not enough. Also I don't know how to do a Mass Balance for this:

-Aveoli
-membrane
-bloodstream
-hemoglobin
-cells
-return via veins back to heart
-pump to alveolus
-capillaries
-where gas exchange takes place
-whole process begins again

Lost
-dissovled into intercellular fluid
-exhaled
-used by microbes
-used by other processes
--some incoperated into h20
-used in sugars and proteins
-diffuse through skin

What am I missing? All your help would be appreciated.