Question

The amino acid binding site of tRNA is-
A. Anticodon
B. DHU arm
C. 3’ end
D. 5’ end

Answer 1

tRNA is an adaptor molecule made up of RNA that acts as the physical connexion between the mRNA and the protein amino acid chain, usually 76 to 90 nucleotides in length.

Complete answer:
Option A is incorrect. At the tip, the anticodon loop has a triplet which pairs the base with the corresponding mRNA codon. Whatever amino acid is attached to the acceptor stem is defined by the anticodon loop, whatever pairs with mRNA. Aminoacyl tRNA synthetase (AATS), the enzyme that chemically binds a tRNA to an amino acid via a high-energy bond, recognises the anticodon loop.
Option B is incorrect. Transfer-RNA has post-transcriptionally modified bases of 7-15 percent. Dihydrouridine (DHU) is almost always located in the DHU loop, which in turn acts as a recognition and binding loop for aminoacyl synthetase. It consists of dihydrouracil, an unusual pyrimidine nucleotide stem and loop. In this loop, there are 15-18 nucleotides, with the stem having 3-4 base pairs and the loop having 7-11 unpaired nucleotides.
Option C is correct. The 3 'end has the sequence as CCA. The amino acid attachment to the 3 'adenosine yields an aminoacyl-tRNA, so the amino acid binding site is called the CCA site. A three-nucleotide acceptor site which includes a free -OH group extends at the 3 ' end of the tRNA molecule, opposite the anticodon. Via its acceptor stem, a specific tRNA attaches to a particular amino acid.
Option D is incorrect. The tRNA's 5'-end is phosphorylated. Translation does not begin simply at the 5'-ends of the mRNA; it begins at particular sites of initiation.

So, the correct answer is Option C.

Note: Francis Crick first proposed the presence of tRNA, based on the premise that there must be an adapter molecule capable of mediating the translation into the protein alphabet of the RNA alphabet. TRNAs, the biological synthesis of new proteins in accordance with the genetic code, are an integral component of translation.