The structure of RNA differs fundamentally from that of DNA in three ways:It forms a single strand sugar-phosphate chain.
The sugar in its nucleotides is ribose.
The base thymine is replaced by the base uracil.
DNA is made of chemical building blocks called nucleotides. These building blocks are made of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases. To form a strand of DNA, nucleotides are linked into chains, with the phosphate and sugar groups alternating.
Each RNA nucleotide consists of three parts: a sugar, a phosphate group, and anitrogen-containing base. The four RNA bases are adenine, uracil, guanine, andcytosine—often referred to as A, U, G, and C. RNA shares three bases in common with DNA: adenine, guanine, and cytosine. Instead of uracil, DNA containsthymine.
