Final answer:
ATP and ADP are not isomers, but different forms of the same molecule involved in energy metabolism.
Step-by-step explanation:
ATP and ADP are molecules that are part of the adenosine nucleotide family, which play a crucial role in energy transfer within cells. ATP (adenosine triphosphate) is the main source of energy for cellular processes, while ADP (adenosine diphosphate) is the product of ATP hydrolysis. These molecules are not isomers, but rather different forms of the same molecule involved in energy metabolism.