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5.1.2. Concept, types and functions of nucleic acids

Concept, types and functions of nucleic acids

The nucleic acids are biomolecules consisting of carbonhydrogenoxygennitrogen and phosphorus. We have already defined them as polymers formed by the union of hydrolyzable monomers, called nucleotides.

Living things have two types of nucleic acidsDNA or DNA (deoxyribonucleic acid) and RNA or RNA (ribonucleic acid) , except viruses that have only one type, either RNA (for example, the polio virus) or DNA (example, bacteriophages), although we will see that viruses are not really living beings.

In DNA, the genetic material, has two functions:

  • Store genetic information: DNA directs protein synthesis, as it contains the information necessary to synthesize an organism's proteins. These proteins are specific to each species and organism, and are responsible for the characteristics of the organism.
  • Passing on the genetic information of one cell to subsequent generations of daughter cells. With the replication or duplication of DNA, cells receive an exact copy of that genetic material that contains the information necessary for the life of the organism.

In this way, hereditary characters are transmitted from parents to children, generation after generation.

The function of RNA is to express genetic information, that is, to execute the orders contained in DNA. Therefore, RNA is responsible for synthesizing proteins from the information contained in DNA. Also, in some viruses it is the hereditary material.

These functions of nucleic acids constitute the "central dogma of molecular biology", in which genetic information from DNA is replicated to DNA, information from DNA is transcribed into RNA, and this information contained in RNA is translated into proteins.

As some viruses have RNA as genetic material, this "dogma" has had to be slightly modified, although with the same idea.