Molecular genetics genetic code

The anticodon region consists of seven nucleotides, and it recognizes the three-letter codon in mRNA (Figure 38-2). The sequence read from the 3 to 5 direction in that anticodon loop consists of a variable base-modified purine-XYZ-pyrimidine-pyrimidine-5h Note that this direction of reading the anticodon is 3 " to 5 whereas the genetic code in Table 38—1 is read 5 to 3 since the codon and the anticodon loop of the mRNA and tRNA molecules, respectively, are antipar-allel in their complementarity just like all other inter-molecular interactions between nucleic acid strands. 

The chemical functioning of a cell is the main objective of Molecular Biology (MB). The isolation, identification, and purification of biomacromolecules could be seen as the first step, in fulfilling this objective. From the catalytic point of view, enzymes are the center of attention. However, the most important biomolecule in the cell is the DNA, in which the genetic code of each enzyme is enclosed, thus representing ultimate target for MB. The biochemical and molecular processes of replication, transcription, and translation become part of the objective. 

Life is strikingly unified at the molecular level one genetic code, limited universal sets of key molecules, common metabolic pathways. 

It required the growth of molecular genetics to probe the differences more intensely, and to discover in the 1980s and early 1990s that the gene coding for one of the two NAT (NAT I and NAT II) enzymes could exist in various forms, and that each form gave rise to a modified form of the enzyme which conferred properties of rapid or slow acetylation. The... 

What then is an individual If not the molecules themselves, then how about the patterns in which they are assembled A glance at a set of identical twins tells you the answer to this second question is no. The molecular patterns in any organism are determined by the organism s genetic code, and identical twins have identical genetic codes. Each member in a set of identical twins has its own unique personality, however, despite the fact that the two persons have identical molecular patterns. 

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