What is DNA, what are its functions and significance for living organisms

DNA is deoxyribonucleic acid, whichensures the preservation and transfer of genetic information. In its structure information about the structure of RNA and all proteins of the body is encrypted. This structure was opened by the Swiss I.Mischler in 1869.

At first, the real properties of DNA were unknown.It was believed that she was responsible for the preservation of phosphorus in the body, and her information was not even known about her properties, since proteins were traditionally considered carriers of hereditary information. Only in 1944, after a series of experiments on the transformation of bacteria, it was clarified that such a DNA, as well as its main functions were determined. After 1952, information about this molecule expanded - it became known that it is the main carrier of information about the structure of the genotype (a set of genes in the body), but at that time nothing was known about its structure, the DNA structure was not deciphered.

Its molecular structure was deciphered in1953 by James Watson and Francis Crick. They determined that DNA is a molecule in the form of a double helix consisting of deoxyribose and phosphate groups that bind to nitrogen bases - adenine, cytosine, guanine and thymine.

It should be noted that the combination of these bases hasclearly defined order - adenine binds only to thymine, and guanine with cytosine, which ensures correct and accurate self-reproduction of the DNA molecule on the principle of complementarity with one of its daughter spirals.

Such a clear definition of the molecular structuremade it possible to better understand what a DNA structure is that preserves the genetic code and is the basis of the heredity of all living organisms, including eukaryotes and some viruses.

The genetic code is stored as a specific nucleotide sequence. Thus, each amino acid of a protein is encoded by three nucleotides, and the sequence of acids is a genes.

With any changes in the structure of DNA,point or gene mutations. Point mutational changes consist of a violation of the molecular structure, which is easily detected by biochemical or hybridological analysis. Gene mutations occur when the sequence of nucleotides changes, which is the result of processes such as transitions, transversions, insertion or loss of individual pairs of nitrogenous bases that disrupt the functioning and properties of DNA.

If such structural changes lead todistortion of important polypeptide sites, then serious violations occur in the body, which predetermine not only the development of organisms, but also their death. So, mutations can arise even during fetal development, which causes the birth of dead or non-viable children. In addition, such violations are at the heart of many congenital malformations that can be transmitted to succeeding generations.

If we summarize the above, then we can makethe conclusion that such DNA is an extremely important structure of genetic information, which is the main component of chromosomes. In addition, DNA is an acid that is responsible for the realization of hereditary information and the functioning of living organisms.