Molecular biologists use several shorthand terms when referring to nucleic acid molecules, such as DNA and RNA, collectively referred to as nucleic acid nomenclature.

The most common is the representation of the base pairs as letters—an adenine nucleotide is abbreviated as A, guanine as G, cytosine as C, thymine as T, and in RNA, uracil as U.

Additionally, the positions of the carbons in the ribose sugar that forms the backbone of the nucleic acid chain are numbered as follows:

The sugar backbone of RNA uses ribose, but DNA uses deoxyribose, which lacks the hydroxyl group attached to the 2' (pronounced "two-prime"; shown above in blue) carbon.

The hydroxyl group attached to the 3' carbon of one base attaches to the phosphate group attached to the 5' carbon of the next base—5' and 3' are often used to indicate the polarity of a DNA strand, e.g. "5' to 3'" and "3' to 5'". This is especially important regarding DNA replication, in which polymerization enzymes move exclusively from 5' to 3' along a DNA strand.

See also

• DNA replication
• Nucleotide

DNA replication | Nucleic acids | Nucleotides | Chemistry | Natural sciences | Physical sciences

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