In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: During glycogen synthesis, a diphosphate derivative of this molecule serves as a carrier for glucose monomers. Cytosine spontaneously deaminates to form this molecule, which can be specifically removed by DNA glycosidase. Marshall Nirenberg showed that a polymer of this molecule, added to a certain cell-free extract, would result in the creation of proteins with radioactive phenylalanine. A "pseudo-" form of this molecule, symbolized psi, is found in one arm of transfer RNA, and it forms two hydrogen bonds with adenine. For 10 points, name this nucleotide that replacing thymine in RNA.
A:
Science