Uracil is a nitrogenous base found in RNA (ribonucleic acid), which plays a crucial role in the synthesis of proteins. It pairs with adenine during the process of transcription, where DNA is converted into RNA. Unlike thymine, which is found in DNA, uracil contains a single ring structure and is classified as a pyrimidine. In addition to its role in RNA, uracil is involved in various metabolic processes. It can be synthesized in the body from cytosine or obtained through dietary sources. Uracil is also important in the regulation of gene expression and cellular functions.