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Biology 2nd Baccalaureate

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2.1. Nucleic acids

Genetic information: nucleic acids

All living things, except viruses, have two types of nucleic acids: DNA and RNADNA is responsible for carrying genetic information, but for that information to be expressed it is necessary that various types of RNA intervene.
Nucleic acids are large polymers formed by the union of monomers called nucleotides linked by a phosphodiester bond, between the phosphate of one nucleotide and the pentose of the next nucleotide.
A nucleotide is made up of three components:
  • pentoseA five-carbon monosaccharide: ribose in RNA and deoxyribose in DNA.
  • phosphoric acid.
  • To nitrogenous base:
    • In DNA: adenine (A), guanine (G), cytosine (C) and thymine (T).
    • In RNA: adenine (A), guanine (G), cytosine (C) and uracil (U).
The information that DNA contains is in how its nucleotides are arrangedThe nucleotide sequence is what determines the genetic information. The DNA consists of two chains of nucleotides.
RNA is made up of a singlechain of nucleotides. Depending on their role, several types of RNA are distinguished: ribosomal RNAmessenger RNA, or transfer RNA.


By Calibuon at English Wikibooks [Public domain], via Wikimedia Commons

By Alejandro Porto [CC BY-SA 3.0], via Wikimdia Commons




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