The DNA is the organic compound that contains the genetic instructions of living beings. It is from these information that is contained in the DNA that all of our cells reproduce, and that all our inherited characteristics of the ancestors are manifested. In the replication of cells, DNA is replicated and each of the cells-daughter is with DNA identical to the DNA of the cell-mother.
The meaning of DNA comes from the English language; it is the abbreviation of Deoxyribonucleic acid. In Portuguese, we would have the term deoxyribonucleic Acid called DNA.
The structure of DNA
The transmission of genetic characteristics is being studied since 1866, when Gregor Mendel made a study which statistical inference pointed to the exact direction that the science of genetics took years later, when there was enough technology to do so.
Until the TWENTIETH century, the discoveries of Mendel, still could not be explained; the evidence was just explained by mathematics, but not if they knew the reasons.
Only in 1953 was that two scientists figured out how was the structure of the DNA molecule. This discovery earned the Nobel Prize in Physiology or Medicine 1962 to scientists James Watson (american) and Francis Crick (british).
The DNA is a long sequence of four nitrogen bases; this sequence is the genetic information. The cells still need molecules of RNA-a messenger for transcribing this information, which will be translated into proteins.
DNA and RNA
RNA is the acronym that refers to Ribonucleic acid (ribonucleic Acid – RNA – in Portuguese).
The DNA and RNA work together in the construction of living beings. The DNA contains the information, which are transcribed by RNA-messenger so that they can be produced all of the proteins that constitute the living beings.
In addition to the RNA-messenger, there are also RNA-ribossômico, which does not act in protein synthesis and, yes, it is part of the structure of ribosomes.
Mitochondrial DNA
Not all our genetic information is contained in the nucleus of the cell. Still there is the Mitochondrial DNA, which is different from the DNA present in the nucleus.
The Mitochondrial DNA is only transmitted by the mother, because at fertilization, only the nucleus of the espermatozoide penetrates the egg and the mitochondria is an organelle that is in the cytoplasm.
It was discovered, in 1986, that all human beings are descended from the same woman, who has lived in Africa for about 200 thousand years. This woman has been dubbed Mitochondrial Eve. The discovery was possible through the analysis of Mitochondrial DNA.