On Sun, 13 Jul 2003 17:43:11 -0700, "Vernon Drake" <vdrake at wgn.net>
>What I would like to know is the "origin" of the ATP. Is this a
>molecule that is just floating around in the cytoplasm or more specificly in
>the mitochondrion just wating to be activated by an enzyme?
It is a metabolite, just like all the amino acids and vitamins and
fats etc in the organism. Some organisms make ATP (or ADP) de novo --
from scratch (from sugar and ammonia), just as they can make amino
acids etc. Others derive it from their food.
ATP is a major cellular chemical apart from its role as an energy
carrier. The A of ATP is adenine, one of the four bases of RNA and
DNA. In fact, one use of ATP itself is as a direct precursor for
Any biochemistry book will show the details of how ATP is made.