Biochemical and genetic experiments have demonstrated that the of tRNA are important for recognition by its cognate aminotransferase-tRNA synthetase.

 Acceptor stem and anticodon loop.

Explanation:

Transfer RNA (tRNA) is a small RNA nucleic acid involved in protein synthesis (translation). Each tRNA molecule has two important areas:

During translation, the ribosome reads the sequence of the mRNA in groups of three bases to assemble the protein. So, in the mRNA chain there are codons, set of three bases, which determine the amino acid to be added to the peptide chain. The tRNA transfers the amino acid to the ribosomes, and then arranges them along the messenger RNA (mRNA) molecule. Then, the tRNA must have an anticodon that is complementary to the codon. Each type of tRNA is specifically combined with 1 of the 20 amino acids to be incorporated into proteins.

This means, during translation, each time an amino acid is added to the growing chain, a tRNA molecule is formed whose base pairs have a complementary sequence with mRNA molecule, ensuring that the appropriate amino acid is inserted into the protein. So, tRNA is a key link between RNA transcription and the translation of that RNA into protein. On the other hand, aminotransferases are enzymes responsible for attaching amino acids to the 3ʹ‐end of cognate tRNAs.

The acceptor stem is the site of attachment of amino acids to tRNA, and anticodon loop is the site of tRNA that is complementary to the codons found in mRNA (that determine the amino acid that will be added) This means, both parts are important for recognition, because the acceptor stem is where the amino acid is, and the anticodon loop ensures that the appropriate amino acid is inserted into the protein.

answer:   option a) glucagon was secreted by his pancreas before he ate the cookies because blood glucose was low. insulin was secreted after he ate the cookies because his blood glucose was high.

explanation: