Video Transcript
An enzyme involved in the process
of translation is peptidyl transferase. What is the role of peptidyl
transferase? (A) To catalyze the formation of
phosphodiester bonds between nucleotides in mRNA. (B) To transfer tRNA molecules to
the mRNA strand to form a polypeptide chain. (C) To catalyze the formation of
peptide bonds between amino acids. (D) To break down the
sugar–phosphate backbone of mRNA molecules.
Translation is the process of
converting the nucleotide sequence in mRNA into a sequence of amino acids or a
polypeptide. Translation is performed by an
organelle called the ribosome. mRNA is sandwiched between the two subunits of the
ribosome, and the codons in mRNA are matched with incoming tRNA molecules carrying
the corresponding amino acid.
There are three different sites in
the ribosome. The A site is where tRNA molecules
carrying amino acids are brought in and matched to codons in mRNA. The P site is where the amino acid
from the incoming tRNA molecule is linked to the existing polypeptide chain. And the E site is where the empty
tRNA molecule that has given up its amino acid can exit the ribosome. The P site contains the peptidyl
transferase enzymatic activity of the ribosome.
Peptidyl transferase catalyzes the
formation of a peptide bond to join the incoming amino acid to the existing
polypeptide chain. Therefore, the correct answer is
(C), to catalyze the formation of peptide bonds between amino acids.
