Cytidine is a nucleoside composed of a pyrimidine base called cytosine and a sugar molecule known as ribose. It plays a crucial role in the structure of RNA (ribonucleic acid), where it helps in the coding, decoding, and regulation of genes. Cytidine is essential for various biological processes, including protein synthesis and cellular metabolism. In addition to its role in RNA, cytidine can be phosphorylated to form cytidine monophosphate (CMP), which is further converted into cytidine triphosphate (CTP). CTP is vital for lipid synthesis and serves as a building block for RNA synthesis. Cytidine is also studied for its potential therapeutic applications in treating certain diseases.