In this article we will discuss about the activation of amino acids and formation of aminoacyl-tRNA. The first step of protein biosynthesis comprises two reactions (see fig. 6-43) catalyzed, for a given amino acid, by one and the same enzyme called activation enzyme, or aminoacyl-tRNA synthetase, or aminoacyl-tRNA ligase. In a first step, the L-amino acid is activated by ATP [...]
In this article we will discuss about the process of biosynthesis of nucleic acids. Biosynthesis of Nucleosides-5'-Triphosphates: Among animals, some amino acids cannot be synthesized and must therefore be supplied through diet (essential amino acids). On the contrary, purine and pyrimidine nucleotides can be synthesized "de novo", from precursors like CO2, NH3, formiate, glycine etc., and this is true of [...]
In this article we will discuss about the fidelity of the replication of DNA. The DNA being the carrier of genetic information it is essential that this information remains correct. But the DNA can be damaged by the action of chemical or physical agents. The cell therefore possesses repair systems which can maintain the integrity of genetic information. It is [...]