The first description of the DNA (deoxyribonucleic acid)chain was done by Watson and Crick in 1953, the nucleotides that constitute the DNA are four: cytosine (C), guanine (G), timine (T) and adenine (A). When doing a model is essential to remember that cytosine ONLY joins guanine and timine only link adenine, this is due to the size and chemical properties of each molecule. Later, another related and similar and molecule was discovered, the ribonucleic acid or RNA, which also is constructed by nucleotides.
In both cases, the nucleotides are compound of 3 main components: a nitrogen base, a pentose and a phosphate. When the molecule lacks the phosphate group, is called nucleoside. Depending on the chain ( DNA or RNA) the nitrogen base derives from purine (adenine and guanine) or pyrimidine (cytosine or timine) just in the RNA instead of timine is uracil (U)
The union is established between adjacent molecules through the phosphate, while among each other through the nitrogen base-remember C=G and T or U=A. The core of each molecule is the pentose. Therefore the best representation of the molecule is attached
References
Watson, J. D., & Crick, F. H. (1953, January). The structure of DNA. In Cold Spring Harbor symposia on quantitative biology (Vol. 18, pp. 123-131). Cold Spring Harbor Laboratory Press.
According to the insurance code of California, the license number of a licensee should be printed at the same size as the fax number, phone number, or address of the licensee on all business cards, printed materials, and price quotes.
The area over which tropical storm-force winds occur is even greater, ranging as far out as almost 300 miles from the eye of a large hurricane. In the northern hemisphere, hurricane winds circulate around the center in a counter-clockwise fashion.
MERCOSUR is an abbreviation of "Mercado Comun del Sur": common market of the South America: most of the eastern South American coutries are members of this common market.
It's a trade block of countries in South America which promotes free trade and free movement of people.
So that they know what the world is about and that they become aware of what is happening out or what will happen if they do certain things.