Reference Work Entry

Encyclopedia of Astrobiology

pp 1463-1465


  • William G. ScottAffiliated withDepartment of Chemistry and Biochemistry, The Center for the Molecular Biology of RNA, University of California at Santa Cruz Email author 


Ribonucleic acid


Catalytic RNA, messenger RNA, nucleic acid, ribosomal RNA, ribozymes, RNA world, RNAi, transfer RNA


Ribonucleic Acid (RNA) is one of two principal types of nucleic acid found in all cellular life. The molecule consists of a polymer of ribonucleoside phosphates, each unit of which, in turn, is comprised of a pyrimidine base or purine base, a ribose sugar, and a phosphate. RNAs encode genetic information (e.g., RNA viruses), serve as intermediates in gene transcription (e.g., mRNA), and also play structural, regulatory, and catalytic (e.g., ribosome) roles in cellular biology.


Central Dogma of Molecular Biology

Francis Crick proposed a simple scheme, shown below, that he entitled “The Central Dogma of Molecular Biology” to serve as a unifying axiom for the emerging field of molecular biology:
$$ {\text{DNA}} \to {\text{RNA}} \to {\text{Protein}} $$
i.e., “DNA makes RNA makes Protein.” Information flow was held ...
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