atp molecules are composed of what three major parts
A single ATP molecule is made up of three parts, adenine, ribose, and phosphates. Adenine and ribose combine to form adenosine, which is then attached to three phosphates to f â¦ orm the high energy ATP molecule.ATP, which stands for adenosine triphosphate, is a single molecule, which includes three phosphate groups.denine, Ribose, and the Triphosphate moiety. The parts of a molecule of ATP are: 1  the purine base, hydrogen; 2  linked to the sugar, glucose; 3  linked to a chain of ten phosphate groups.