Nucleic acids
The nucleic acids how are the DNA and the RNA are the
responsibles of the genetic information.
The nucleic acids are formed by nucleotide chains, are
composed by a nitrogen base, a phosphate group and a sugar. Depended for the
sugar that this take is a DNA or RNA. The nitrogen bases can be of two groups.
Pyrinidines: Cytosine, Timine and Uracil
Purines: Guanine and Adenine
In the DNA can found matings of Timine, Cytosine with
Guanine in the nucleotide chains.
In the other case, the RNA have Uracils, Adenine or
Cytosine with Guanine in their chains.
Chemical nature of the DNA
Correspond at two chains antiparallel of nucleotides
united for phosphate groups, with their bases matings to under and rolled up
around of a central imaginary axis, this making a double propeller. This has
how pentose the desoxyribose, that link bye the phosphate group forming the
chain esquelet. In under are located the nitrogen bases that mating for th
formation of hifrogen bonds. Always mating a nitrogen base purine with a
pyrimidine, for that the secuence of both chains are complementary.
All is in the next image
DNA funtion:
The genetic information are stored in the secuence of
nucleotides of DNA, serve to two purposes:
#Is the source of information for the synthesis of all
molecules of proteins of the cell and the organism.
#give the information inherited by the daughter´s
cells of the progenitor.
Both funtions require that the cells of DNA serve how
mold, in the first option to serve for the transcription of the information, in
the second case for the replication of the organic codes that contain the
estructure of the living being.
Chemical nature of the RNA
In this is present the sugar “ribose”. This indicate o
the position 2 of the ring of sugar have a hidroxile group (OH) free. For this
case, the RNA is chemicaly inestable, for that in aqueous solution hydrolyzes
easily. In the RNA the base mating with tha A is U in difference of the DNA, in
this case theA mating with T, forming the nucleotide chains.
Several types of RNA are distinguished depending, above all, on their
molecular weights:
Messenger
RNA
It is synthesized on a DNA template by the transcription
process by which the RNA is copied from the DNA template, passes into the
cytoplasm and serves as a guideline for the synthesis of proteins (go to the
ribosomes for its use).
Ribosomic
RNA
Ribosomal RNA (RNAr) as its name says is present in
ribosomes, intracellular organelles involved in protein synthesis. Its function
is to read the mRNAs and form the corresponding protein, in short, it receives
what the messenger RNA brings and with the code and the information elaborates
one or more proteins.
Transfer
RNA
They are short chains of a basic structure, which can
bind specifically to certain amino acids.