Nucleic Acids

Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

Nucleic Acids


(also polynucleotides), major biopolymers that are found in every cell of every living organism. Nucleic acids were discovered in 1868 by the Swiss scientist F. Miescher in the nuclei of cells that were isolated from pus and from salmon sperm; later, these biopolymers were also found in the cytoplasm. Two main kinds of nucleic acids are distinguished: deoxyribonucleic acid (DNA), which is found mostly in the nucleus, and ribonucleic acid (RNA), which is found mostly in the cytoplasm.

Nucleic-acid molecules consist of long polymer chains with a molecular weight ranging from 2.5 × 104 to 4 × 109. Each chain is constructed from monomeric units called nucleotides in such a way that the hydroxyl groups at the 3′ and 5′ carbon atoms in the carbohydrate portions of adjacent nucleotides are bound by a phosphate group. Ribose is the carbohydrate component of RNA, while the nitrogen components are the purine bases adenine and guanine and the pyrimidine bases uracil and cytosine. Deoxyribose is the carbohydrate component of DNA, and uracil is replaced by thymine, or 5-methyluracil. The phosphate radical and the carbohydrate are the nonspecific portion of a nucleotide, and the purine or pyrimidine base are the specific portion. Most nucleic acids also contain small quantities of minor bases—usually methylated purine and pyrimidine derivatives. Nucleic acid chains contain from tens to thousands of nucleotides, arranged linearly in a definite sequence that is unique to each nucleic acid. Thus, both RNA and DNA consist of a huge number of individual compounds. The linear sequence of the nucleotides determines the primary structure of a nucleic acid. The secondary structure of a nucleic acid results from the mutual, complementary attraction of certain pairs of bases. Specifically, guanine is bound to cytosine and adenine to uracil or thymine by hydrogen bonds and by hydrophobic interactions.

The biological function of the nucleic acids is to store, determine, and transmit hereditary information. This information is recorded in the form of a sequence of nucleotides—the genetic code. The replication of DNA occurs during mitotic cell division; as a result of replication, each daughter cell receives the same amount of DNA and thus contains a program for developing all the characteristics of the parent cell. In order to convert this genetic information into specific characteristics, RNA molecules are synthesized on a template of DNA molecules—a process called transcription—and subsequently proteins are synthesized with the participation of several kinds of RNA—a process called translation.

Great advances in molecular genetics and molecular biology were made possible as a result of research conducted between the early 1950’s and the 1970’s on the structure and function of nucleic acids. The most important achievement in the study of the chemistry and biology of the nucleic acids was the double-helix model of the DNA molecule, which was proposed in 1953 by J. Watson and F. Crick. This model helped explain many of the properties and biological functions of DNA.

Nucleic acids have also been found in organelles, for example, chloroplasts and mitochondria, where their functions are now under study. Comparative analysis of nucleic acids in different groups of organisms plays an important role in solving some problems in taxonomy and evolution. Every species of organism carries its own characteristic type of DNA and RNA. The degree of structural resemblance between nucleic acids of different species is indicative of the phylogenetic similarity of the organisms.


Nukleinovye kisloty. Moscow, 1963. (Translated from English.)
Watson, J. Molekuliarnaia biologiia gena. Moscow, 1967. (Translated from English.)
Davidson, J. Biokhimiia nukleinovykh kislot. Moscow, 1968. (Translated from English.)
Khimiia i biokhimiia nukleinovykh kislot. Edited by I. B. Zbarskii and S. S. Debov. Leningrad, 1968.
Mirskii, A. “Otkrytie DNK.” In Molekuly i kletki, fasc. 4. Moscow, 1969. (Translated from English.)
Organicheskaia khimiia nukleinovykh kislot. Moscow, 1970.
Metody issledovaniia nukleinovykh kislot. Moscow, 1970. (Translated from English.)
Stroenie DNK i polozhenie organizmov v sisteme. Moscow, 1972.
Hofmann, E. Dynamische Biochemie, 2nd ed., vol. 1: Eiweise und Nucleinsäuren als biologische Makromoleküle. Berlin, 1970.


References in periodicals archive ?
This work is significant because it supports the idea that these component molecules may have been around on the early Earth, reacted together, and survived because they were useful to proteins and nucleic acids.
The industrial experience held by Genset Oligos will make Proligo a fully integrated supplier of nucleic acid specialties (genomics and genetic medicine).
Shortly thereafter, Orgel and his colleagues devised an alternate scheme, also rooted in the chemistry of the two nucleic acids.
Indeed, Fox's "thermal protein first paradigm" runs counter to a central tenet of cellular biology--namely, that nucleic acids had to exist before any cell could arise that could properly be called living.
The gene or nucleic acid molecule can include single or double stranded nucleic acids corresponding to coding or non-coding strands of the caspase-14 nucleotide sequence.
At the very least, they say, their self-copying molecule should help scientists address a profound question of biochemistry: How did nucleic acids such as DNA and RNA come to embody a blueprint for making proteins -- the stuff of hair, muscles and key biological molecules such as enzymes?
Cambridge, MA) has patented a method for providing isolated nucleic acids molecules, designated NIP2b, NIP2cL, and NIP2cS nucleic acid molecules, which encode novel NIP2 family members.