Question

tRNA carries aminoacid on .......... site.

• A. 5' end
• B. 3' end
• C. Aminoacyl synthetase binding loop
• D. Anticodon

Answer 1

Answer: (B)

3' end

All tRNAs have about 73 to 93 nucleotide that folds into four base-paired stems and three loops. The 3' end has CCA sequence. Attachment of an amino acid to the 3 adenosine yields an aminoacyl-tRNA. Transfer-RNA has 7-15% post-transcriptionally modified bases. Dihydrouridine (D) is nearly always found in the D-loop and ribothymidine (T) and pseudouridine in the T psi C loop. The D-loop serves as aminoacyl synthetase recognition and binding loop while the T psi C loop binds the charged tRNA-amino acid to the ribosome. The anticodon loop has triplet at the tip which base pairs with the corresponding codon in mRNA. Thus, tRNA carries amino acid on 3' sites.