Background Information

Background Information:

DNA is formed by two chains which are polynucleotidic which form a double helix. The sugar in
the nucleotides always are in the deoxiribose group, and the bases must be A, G, C and T. This
model was described by Watson and Crick in 1953. Both chains are joined by their bases
(which are joined by hydrogen bonds) and are parallel and anticomplementary.

Complementarity means that if one chain is found, somewhere, the A base, in the same place
but in the other chain the T base will be found. Therefore, in a double strand of DNA, A=T and
G=C. This happens every time except for mutations. So, we can figure out the second strand by
having the first one, and vice versa.
DNA has two fundamental functions on human beings:

1) The DNA in the chromosomes is the material by which genes are formed. It contais the 

information necessary that allows the synthesis of every protein in a living being. This 

genetic information which was inherited from our progenitors must be decodified in 

order to be used by the cell, and this process is realized in tho stages:

- Transcription of the genetic information contained in a gene, which allows the cell to 

copy information from the other chains of DNA and copy them which is RNA.

- Translation of the message from the sequence of RNA bases corresponding to a gene, 

it is realized in the ribosomes, which convert this message into a sequence of amino 

acids from a certain protein. 

2) Replication: each molecule of DNA may originate several replicas of itself. Each cell, 

before its division, copies its genes so that its successors contain the same genetic 

dotation as itself.  Therefore, the genetic information will be transmitted from every 

generation.

(ScienceDaily, 2015)