question_answer

A synthetically prepared mRNA contains repetitive AU sequences. The mRNA was incubated with mammalian cell extract which contains ribosomes, tRNAs and all the factors required for protein synthesis. Assuming no initiation codon is required for protein synthesis, which of the following peptides will most likely be synthesised?

A) A single peptide composed of the same amino acid sequence.

B) A single peptide with alternating sequence of two amino acids.

C) A single peptide with alternating sequence of three amino acids.

D) Three different peptides, each sequence composed of a single amino acid.

Correct Answer: B

Solution :

Synthetically prepared mRNA sequence and the polypeptide synthesised from it is given below:

This mRNA with repetitive AU sequences codes for a single peptide with alternating sequence of two amino acids.