Question

The amino acid attaches to the tRNA at its:

• A. Anticodon site
• B. 3'- end
• C. DHU loop
• D. 5'- end

Answer 1

The correct option is B 3'- end

tRNA structure:

tRNA or transfer RNA is a type of RNA that carries and transfers amino acids to ribosomes during the synthesis of polypeptides in translation.

It consists of the following parts:

• 5’ end
• 3’end
• Anticodon loop
• DHU loop
• Variable loop
• $T\psi C$ loop

5’ end:

The 5’ end of tRNA remains normally free


3’ end:

The 3’ end of tRNA binds to the amino acid. It requires ATP for amino acid binding. Thus, this process of attachment of an amino acid to the 3’ end of tRNA is called charging of tRNA or aminoacylation of tRNA.


DHU loop:

The DHU loop of tRNA (first loop from 5’ end) contains some unusual bases such as dihydrouridine. The enzyme aminoacyl tRNA synthetase recognises DHU loop of tRNA for charging of tRNA.

$T\psi C$ loop:

The $T\psi C$ loop (first loop from 3’ end) is the binding site for ribosome.


Variable loop:

The variable loop sits between the anticodon loop and the$T\psi C$ loop. It varies in size from 3 to 21 bases in different tRNAs.

Final answer:b. 3' end