What composes a nucleotide of RNA?
Each nucleotide in RNA contains a ribose sugar, with carbons numbered 1′ through 5′. A base is attached to the 1′ position, generally adenine (A), cytosine (C), guanine (G) or uracil (U). Adenine and guanine are purines, cytosine and uracil are pyrimidines. A phosphate group is attached to the 3′ position of one ribose and the 5′ position of the next. The phosphate groups have a negative charge each at physiological pH, making RNA a charged molecule (polyanion). The bases may form hydrogen bonds between cytosine and guanine, between adenine and uracil and between guanine and uracil.[1] However other interactions are possible, such as a group of adenine bases binding to each other in a bulge,[2] or the GNRA tetraloop that has a guanine–adenine base-pair.[1] An important structural feature of RNA that distinguishes it from DNA is the presence of a hydroxyl group at the 2′ position of the ribose sugar. The presence of this functional group causes the helix to adopt the A-form geometry rat
