Protein biosynthesis occurs in three different locations of a cell
During protein biosynthesis, the nucleotide sequence of mRNA is translated into an amino acid sequence. The “interpreters” aretransfer ribonucleic acids (tRNAs), small RNAs of 75 to 110 ribonucleotides, which have a defined structure with hairpins and loops. One loop exhibits the anticodon, which is complementary to the mRNA codon. For each amino acid there exists at least one and sometimes several tRNAs. The covalent binding of the amino acid to the corresponding tRNA is catalyzed by its specificaminoacyl tRNA synthetase. With the consumption of ATP a mixed anhydride aminoacyl-AMP is synthesized as an intermediate prior to the binding of the amino acid to the 3’ OH of the tRNA (Fig. 21.1).
In a plant cell, protein biosynthesis takes place in three different locations. The translation of the nuclear encoded mRNAs proceeds in the cytosol, and that of the mRNAs encoded in the plastidic or mitochondrial genome takes place in the plastid stroma and mitochondrial matrix, respectively.
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