Fundamental theory of molecular biology
By fundamental theory of molecular biology , the biologists represent the diagrammatic model of the conservation and the use of genetic information. DNA is the stable and transmissible support of the genetic information which defines the biological functions of an organization (reproduction, nutrition, excretion, action on the environment, communication, etc). It is transcribed in ARN (a similar language) which has only one temporary life, this ARN provides either a structural function (skeleton of nucléo-proteinic complexes), or an enzymatic function (synthesis of proteins, export of proteins, epissage of the ARNm Eucaryote S, etc), or a function of transport of genetic information. The ARN of the type messenger (ARNm) is " traduit" in Protein S by the Ribosome (complex nucléo-proteinic). One speaks about Traduction of protein ARNm because the language changes.
The fundamental theory is summarized as follows: the DNA directs its own replication in identical DNA, like its transcription in ARN, being able or not to be translated into proteins.
When Francis Crick formulated this theory in 1958, it used the word Dogme, which lends here to confusion, because it is indeed of a scientific Théorie, and not about doctrines established like an undeniable truth. Crick thought wrongly that the dogma term returned to " an idea which is not supported by evidence rationnelles". Its error was unfortunately ratified by the use, and one usually speaks about " dogma of biology moléculaire" to indicate the relations between DNA, ARN and proteins. But this theory is like any scientific theory prone to modification, and the assumptions to which it has recourse are refutable by experiments. What it is more judicious to call the " theory centrale" molecular biology thus was modified/adjusted with the wire of the scientific discoveries.
Thus, the initial theory did not consider the possibility of a " retour" with a form DNA starting from the ARN. However it was highlighted at the Rétrovirus the existence of a Enzyme (proteinic catalyst), the Transcriptase reverses, capable of rétrotranscrire the viral ARN in DNA. This discovery does not give completely causes the central theory of molecular biology of it, but makes it possible to specify the bonds existing between the various molecular supports intervening in the expression of genetic information.
See too
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