Nucleic acid

Nucleic acid
One of the molecules in the chromosomes of living cells and viruses that plays a central role in the storage and replication of hereditary information and in the expression of this information through protein synthesis. The two chief types of nucleic acids are: {{}}DNA (deoxyribonucleic acid) which contains the hereditary information in humans and RNA (ribonucleic acid) which delivers the instructions coded in this information to the cell’s protein manufacturing sites. History: In 1869 Friedrich Miescher developed ways of isolating intact nuclei from cells and analyzing their chemical content. From the nuclei he extracted substances rich in phosphorus and nitrogen. They came to be known as "nucleic acids." Miescher predicted that they would someday be considered as important as proteins. The substances turned out to be deoxyribonucleic acid (DNA) which was found by Avery, MacLeod and McCarty in 1944 to be the genetic material. They proved this clearly by using bacterial DNA to change (transform) the genetic material of other bacteria.
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A family of macromolecules, of molecular masses ranging upward from 25,000, found in the chromosomes, nucleoli, mitochondria, and cytoplasm of all cells, and in viruses; in complexes with proteins, they are called nucleoproteins. On hydrolysis they yield purines, pyrimidines, phosphoric acid, and a pentose, either d-ribose or d-deoxyribose; from the last, the nucleic acid s derive their more specific names, ribonucleic acid and deoxyribonucleic acid. Nucleic acids are linear ( i.e., unbranched) chains of nucleotides in which the 5′-phosphoric group of each one is esterified with the 3′-hydroxyl of the adjoining nucleotide.
- infectious n. viral n. that can infect cells and bring about the production of viruses.

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nu·cle·ic acid n(y)u̇-.klē-ik-, -.klā- n any of various acids (as an RNA or a DNA) composed of nucleotide chains

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either of two organic acids, DNA or RNA, present in the nucleus and in some cases the cytoplasm of all living cells. Their main functions are in heredity and protein synthesis.

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see under N.

Medical dictionary. 2011.

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Look at other dictionaries:

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  • nucleic acid — u*cle ic ac id (n[=oo]*kl[=a] [i^]k [a^]s [i^]d or n[=oo]*kl[=e] [i^]k), n. (Chem., Biochem., Genetics) A natural or synthetic polymer consisting of chains of ribonucleotide or deoxyribonucleotide units. Note: The nucleic acids are vital… …   The Collaborative International Dictionary of English

  • nucleic acid — [no͞o klē′ik, nyo͞oklē′ik; no͞oklā′ik, nyo͞oklā′ik] n. any of a group of essential complex organic acids found in all living cells: the two types are DNA and RNA and consist of long chains of nucleotide units with each unit composed of phosphoric …   English World dictionary

  • nucleic acid — nucleic acid. См. полинуклеотид. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • nucleic acid — ► NOUN Biochemistry ▪ a complex organic substance, especially DNA or RNA, whose molecules consist of long chains of nucleotides …   English terms dictionary

  • nucleic acid — /nooh klee ik, klay , nyooh /, Biochem. any of a group of long, linear macromolecules, either DNA or various types of RNA, that carry genetic information directing all cellular functions: composed of linked nucleotides. [1890 95; NUCLE(US) + IC;… …   Universalium

  • nucleic acid — UK [njuːˌkliːɪk ˈæsɪd] / US [njuˌklɪɪk ˈæsɪd] / US [njuˌkleɪɪk ˈæsɪd] noun [countable/uncountable] Word forms nucleic acid : singular nucleic acid plural nucleic acids biology an acid such as DNA or RNA that is found in the cells of all living… …   English dictionary

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  • Nucleic acid design — can be used to create nucleic acid complexes with complicated secondary structures such as this four arm junction. These four strands associate into this structure because it maximizes the number of correct base pairs, with A s matched to T s and …   Wikipedia

  • Nucleic acid thermodynamics — is the study of the thermodynamics of nucleic acid molecules, or how temperature affects nucleic acid structure. For multiple copies of DNA molecules, the melting temperature (Tm) is defined as the temperature at which half of the DNA strands are …   Wikipedia

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