MMSC490 Quiz 9 (100% correct solutions)

Which of the following statements regarding tRNAs is false? A) tRNAS are approximately 70-80 bases long and form a cloverleaf structure. B) All tRNAs have a CCA sequence at their 3′ terminus. C) tRNAs differ in sequence only at the anticodon. D) There are several modified bases present in mature tRNAS. correct answers C) tRNAs differ in sequence only at the anticodon. The function of aminoacyl tRNA synthetases is to _______. correct answers covalently attach amino acids to their corresponding tRNA molecules. Which of the following statements about the attachment of amino acids to tRNAs is false? A) The amino acid is first joined to AMP, forming an aminoacyl AMP intermediate. B) Two molecules of ATP are required for the process, one at each step. C) Aminoacyl tRNA synthetases catalyze the reaction. D) The amino acid is transferred to the 3′ end of the tRNA. correct answers B) Two molecules of ATP are required for the process, one at each step. The primary function of rRNAs in the ribosome is ________. correct answers to catalyze peptide bond formation. The first amino acid of eukaryotic polypeptides is _________. correct answers methionine The initiator codon in prokaryotes is _______. correct answers recognized via the Shine-Dalgarno sequence. Which of the following statements about translational initiation is false? A) In prokaryotes, ribosomes often bind the mRNA and can scan 5′ or 3′ until recognizing a Shine-Dalgarno sequence. B) Viral mRNAs contain internal ribosome entry sites that allow ribosomes to bind to an internal site of the mRNA.