Microeletronics

Pagina 1

17 MAGGIO 2018 Dna chemically consists of a couple of molecule complementary each other. These are composed by 4 types of monomers called neuclotides. The ttwo chains have a some kind of direction, a sort of arrow oriented from 3’ to 5’. The nucleotides are made of a phosphate, a five- carbon sugar and a nitrogen base that’s the changeable one  give to each monomer its characteristics. The link to the base is located on C1’, the phosphate on C4’-C5’. The four bases are call thymine, adenosine, cytosine and guanine. Each base has a particular affinity with another one (C -G, A-T). The specific bond is much stronger the unspecific ones. The specific one can keep the DNA integer, when the other ones are found the molecule can be easily broken with a little increase of temperature. At room temperature the hydrogenus bonds are though. At 95 °C the DNA denaturates dividing into chains; cooling back the temperature the chains tend to recombine or with the same chain or with a complementary one. DNA single and doubl e chain do not absorb the same amount of UV radiation. We can define a turning point (when half DNA is coupled and the other open) called T -melting, that’s not a single value, varies: depends on the number of neuclotide, the higher amount of neuclotid es is present, the higher energy to break the bonds is required (i.e. higher Tm). In particular, the higher CG couples are present, the more it increases. NB: notice that the red curve tends to reach the blue one since the single chains increase. The same kind of mechanism happens in PC and cell. We will look at the data stored in DNA. DNARNAProtein RNA contains instruction to build proteins. A byte can correspond to the amminocosi. DNA is the most efficient memory, in a single gram of it there are 10^21 infor…