That friends today I will talk a bit about DNA or as few know it as Deoxyribonucleic Acid is a large molecule located in all living cells, which has the genetic data of a living being and certain viruses, considered an accumulation of genes long-term. This keeps for many years and at the same time transmits this data from generation to generation, allowing the development of the functions of the organism, using these data -each gene- for the production of proteins. DNA is a long polymer formed by repetitive units, the nucleotides. A double strand of DNA measures from 22 to 26 angstroms (2.2 to 2.6 nanometers) wide, and one unit (one nucleotide) is 3.3 Å (0.33 nm) long. Although each individual unit that repeats is very small, the DNA polymers can be massive molecules that contain millions of nucleotides. For example, the longest human chromosome, chromosome number 1, is approximately 220 million base pairs.
Deoxyribonucleic acid or DNA is made up of alternating units of phosphate and sugar groups. The sugar in DNA is a pentose, specifically, deoxyribose.
Phosphoric acid:
Phosphodiester bond. The phosphate group (PO43-) joins the carbon5 'of the sugar of a nucleoside with the carbon 3' Its chemical formula is H3PO4. Each nucleotide can contain one (monophosphate: AMP), two (diphosphate: ADP) or three (triphosphate: ATP) phosphoric acid groups.
Deoxyribose:
It is a monosaccharide of 5 carbon atoms (unpent) derived from ribose, which is part of the nucleotide structure of DNA. Its formula is C5H10O4. One of the main differences between DNA and RNA is sugar because in RNA the 2-deoxyribose in DNA is replaced by a pesto alternative, ribose.
The sugar molecules are bound together through phosphate groups, which form phosphodiester bonds between the third carbon atoms (3 ',' three cousins ') and fifth (5', 'five cousins') of two adjacent sugar rings. The formation of asymmetric links implies that each strand of DNA has a direction. In a double helix, the direction of the nucleotides in one strand (3 '→ 5') is opposite to the direction in the other strand (5 '→ 3'). This organization of the DNA strands is called antiparallel; they are parallel chains, but with opposite directions.
Nitrogenous bases:
The four major nitrogenous bases found in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T). Each of these four bases is linked to the sugar-phosphate framework through the sugar to form the complete nucleotide (base-sugar-phosphate).
Thymine:
In the genetic code is represented by the letter T. It is a pyrimidine derivative with an oxo group in positions 2 and 4 and a methyl group in position 5. It forms the nucleoside thymidine (always deoxythymidine, since it only appears in the DNA) and the nucleotide thymidine monophosphate (dTMP). In DNA, thymine is always paired with the adenine of the complementary chain by means of 2 hydrogen bonds, T = A. Its chemical formula is C5H6N2O2 and its nomenclature 2,4-dioxo, 5-methylpyridine.
Cytosine:
In the genetic code, it is represented by the letter C. It is a pyrimidine derivative, with an amino group in position 4 and an oxo group in position 2. It forms the nucleoside cytidine (deoxycytidine in DNA) and the cytidylate or (deoxy) cytidine monophosphate ( dCMP in the DNA, CMP in the RNA). The cytosine is always paired in the DNA with the guanine of the complementary chain by a triple bond, C≡G. Its chemical formula is C4H5N3O and its nomenclature 2-oxo, 4 aminopyrimidine. Its molecular mass is 111.10 units of atomic mass.
_
I invite you to comment on this topic, I await your comments
