Microbiology and Immunology

Ribonucleic acid (RNA) WORLD OF MICROBIOLOGY AND IMMUNOLOGY

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Diagram showing specific base pairing found in DNA and RNA.

them combines with one of the riboses of the backbone to

form a nucleoside, such as adenosine, guanosine, cytidine,

and uridine. The combination of a ribose, a phosphate, and a

given nitrogenous base by its turn results in a nucleotide, such

as adenylate, guanylate, cytidylate, uridylate. Each phospho-

diester bridge links the 3’ carbon at the ribose of one

nucleotide to the 5’ carbon at the ribose of the subsequent

nucleotide, and so on. RNA molecules fold on themselves and

form structures termed hairpin loops, because they have

extensive regions of complementary guanine-cytosine (G-C)

or adenine-uracil (A-U) pairs. Nevertheless, they are single

polynucleotide chains.

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