Question

Which is correct about the peptide elongation by ribosome?

Select one:

a. Addition of a new amino acid is achieved by peptide transfer from the A site tRNA to the P site tRNA.

b. Translation is not affected by the cellular availability of GTP.

c. Peptide bond formation is catalyzed by enzymatic proteins in ribosome.

d. The peptide bond is formed by a nucleophilic attack of the A-site NH2- onto the P-site -COOH.

e. None of these

Answer 1

Option D

(In case D is not right, than E will be correct)

First option is incorrect because during the process of translation, peptide transfer occurs from P site to A site.

Second option is incorrect because GTP is required during elongation and termination of translation.

Third option is incorrect because peptide bond formation occurs with the help of RNA-based enzymes which are present in the ribosome.

Fourth option is correct because peptide Bond formation occurs by the nucleophilic attack of A site NH2 onto ester of carbonyl group of P site amino acid.

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