Ribotide

Ribotide is a term historically used to refer to ribonucleotides, the nucleotides that contain a ribose sugar. In contemporary usage, ribonucleotide is the preferred term, while ribotide appears in older literature or in contexts emphasizing the ribose-bearing nature of the molecule.

A ribonucleotide consists of three parts: a nitrogenous base (adenine, guanine, cytosine, or uracil) attached to a ribose sugar, which in turn is linked to one to three phosphate groups at the 5' position. In RNA, the common monophosphates are AMP, GMP, CMP, and UMP; the triphosphate forms (ATP, GTP, CTP, UTP) are essential substrates for RNA synthesis and serve as energy carriers in various cellular processes. The ribose sugar in ribonucleotides has a hydroxyl group at the 2' position, distinguishing them from deoxyribonucleotides used by DNA.

Biological roles of ribotides include serving as the building blocks of RNA, participating in energy transfer (as ATP and GTP), and acting as precursors for nucleotide cofactors and signaling molecules. The distinction from deoxyribonucleotides is crucial for the structure and function of RNA versus DNA. While the term ribotide may still be encountered in some texts, ribonucleotide is the standard nomenclature in modern biochemistry and molecular biology.