The structure of ATP is shown above. Based on the structure, what macromolecular do you think that ATP would be a precursor for which macromolecule? 
a) protein

b) DNA

c) RNA

d) lipids

e) glycogen

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The answer is C. If we remember, ATP stands for Adenosine TriPhosphate, and thus, based on just pure nomenclature, we know that it is some sort of nucleic acid (adenosine = adenine without the phosphate group; in other words adenosine is the nucleoside for the adenine nucleotide). Thus, we now narrow the answer choices to either B or C. In this case, the next thing is to look at the sugar. If the sugar is deoxyribose, then the macromolecule is DNA, and if it is ribose, then the macromolecule is RNA. In this case, the sugar is ribose, and thus, the macromolecule that ATP is a precursor for is RNA. 

**Another important note for this question is the fact that prior to be added to DNA or RNA, nucleotides are present in the triphosphate form and it is the hydrolysis of the pyrophosphate that provides the energy for addition. In this case, the ATP is the triphosphate form of the adenine nucleotide prior to its addition to RNA.**