What remains after a phosphate group is removed from ATP?

When a phosphate group is removed from ATP (adenosine triphosphate), what is left is adenosine diphosphate (ADP). ATP consists of three phosphate groups, and the energy stored in these phosphate bonds is utilized by the cell for various functions, including muscle contraction, active transport, and biochemical reactions.

The removal of one phosphate group from ATP results in the formation of ADP, which has only two phosphate groups. This reaction is often catalyzed by enzymes known as ATPases, which facilitate the hydrolysis of ATP. The process releases energy that the cell can use.

Therefore, the presence of two phosphate groups in ADP is what makes it the correct answer, as it directly follows the dephosphorylation of ATP. The other options, while related to ATP in some way, do not accurately describe the molecule that remains after the specific removal of a phosphate group from ATP.