Question

What polypeptide sequence would you expect to be translated from the following unprocessed eukaryotic RNA sequence 3ʼ AAG AUC UAA UAU UAC ACC GUA
5ʼ (the third and forth codons from the left are introns).
Select one:

a. N-terminus Met-Pro-His-Tyr- Asn-Leu-Glu C-terminus

b. None of these answers is correct
c. N-terminus Met-Pro-Asn-Leu-Glu C-terminus
d. C-terminus Lys–Ile C-terminus

e. N-terminus Lys-Ile C-terminus

Answer 1

Since the third and forth codons from the left are introns, so they will be spliced out from the given unprocessed eukaryotic sequence. So after intron splicing, the following sequence is further translated into Amino Acid sequence:

3' - AAG AUC UAC ACC GUA - 5'

Also, the translation process takes place from 5' end towards 3' end. So we need to reverse the given mRNA sequence in order to translate it into its respective amino acids.

5' - AUG CCA CAU CUA GAA - 3'

Now, its corresponding polypeptide chain will be :

Met-Pro-His-Leu-Glu

AUG codes for Methionine, CCA codes for Proline, CAU codes for Histidine, CUA codes for Leucine and finally GAA codes for Glutamate.

So the correct option is b) None of these answers is correct.

{ P.S. If the question explicitly mentions that Introns are "NOT" to be spliced, then the correct answer would have been a) Met-Pro-His-Tyr-Asn-Leu-Glu }

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