Which of the following is not a true statement about atp? a. atp consists of ribose, adenine, and three phosphate groups. b. adp is produced when atp releases energy. c. atp provides energy for the mechanical functions of cells. d. used atp is discarded by the cell as waste.

D. Used ATP becomes ADP, which then is cycled back through the system to add  a extra Phosphate group, which then turns it back into ATP. It gives off that Phosphate group as energy to a part of the cell then cycles again. ATP does not become 'waste' when it is used and can be reused.