Which base does RNA contain in place of thymine?

RNA contains uracil in place of thymine, which is found in DNA. This difference is significant because while both RNA and DNA are nucleic acids that play vital roles in genetic information and protein synthesis, they have distinct structural features that affect their function. Thymine in DNA forms stable hydrogen bonds with adenine, which assists in the double-helix structure. In RNA, uracil replaces thymine, pairing with adenine during processes like transcription, where DNA is converted into RNA. This substitution is crucial for the various roles of RNA, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). The presence of uracil also allows RNA to be more versatile and reactive, fitting its functions in the cell.