how many amino acids will be coded by mRNA sequence- 5`CCCUCAUAGUCAUAC3` if adenosine residue is inserted after 12th nucleotide?

Asked by Mandal | 4th Jan, 2017, 10:41: PM

Expert Answer:

The mRNA sequence provided does not have a start codon AUG. For the process of translation to occur the ribosome must find the start codon.

Still, let us assume that the process of translation has started. ,

In the given mRNA sequence, the 12th nucleotide is Adenosine (A).

Therefore, after inserting one more adenosine after the existing adenosine residue, we have the mRNA sequence as:

If you read the sequence carefully, you would observe that addition of an adenosine after the 12th nucleotide would not make any difference because the 3rd codon is UAG which is the stop codon. This will cause the process of translation to cease.

As the bases read in triplets and 1 triplet codes for one amino acid, we have only two amino acids that would be coded by this sequence.

Answered by Sheetal Kolte | 5th Jan, 2017, 11:40: AM