In the DNA helix, the GC and AT base pairs
In the DNA helix, the GC and AT base pairs
Select an option to attempt
Correct Answer: Option A
Explanation
In the tRNA cloverleaf secondary structure: The 3' end has the universal sequence 5'-CCA-3' (the acceptor stem, also called the amino acid acceptor stem or 3' acceptor arm). The cognate amino acid is covalently attached (aminoacylation) via an ester bond between its carboxyl group and the 2'- or 3'-OH of the terminal adenosine (A76) of the CCA sequence. The reaction is catalysed by aminoacyl-tRNA synthetase (aaRS) using ATP (forming aminoacyl-AMP then transferring to tRNA, releasing AMP + pyrophosphate). Each of the 20 amino acids has its own cognate aaRS. The anticodon loop (at the opposite end of the tRNA) base-pairs with the complementary codon on mRNA at the ribosomal A site during translation.