The primary transcript or pre mrna of a nuclear gene in
achimpanzee has the sequence
5'-g-exon1-agguaagc-intron-caguc-ex on2-a-3'
after the intron has been excised, what is the most
likelysequence of the mrna?

The most likely sequence of the mRNA is 5´- G - exon1 - AGUC - exon2 -A -3´.

Explanation:

Introns are non-encoding sequences that produce interruptions in a eukaryotic gene. On the contrary, the encoding sequences are called exons. Most of the eukaryotic, multicellular genes contain introns in their sequences. Introns are transcripted to mRNA molecules and get excised before traduction by a specific mechanism. This occurs before the mRNA leaves the nucleus. The introns are excised and the exons must splice to form a unique molecule. This process is known as "splicing".

There are specific splicing sites, which are the limits between introns and exons. By comparing the nucleotidic sequences of mRNA and the structural gene, joints between introns and exons can be determined. These joints are characterized by short highly conserves nucleotide sequences. So each intron has a specific extreme according to these highly conserved termini.

A generic intron sequence in the DNI strand is 5´-GT --- AG-3´.  So the intron begins with the dinucleotide GT and ends with the dinucleotide AG. The RNA sequence, in this case, is 5´-GU --- AG-3´.  

So these dinucleotides GU and AG describe the splicing areas. The cut must be performed in a place where these dinucleotides are located.

In the exposed example, the pre mRNA of a nuclear gene in a chimpanzee has the sequence 5'-G-exon1-AGGUAAGC-intron-CAGUC-exon2-A-3'.

The intron dinucleotides extremes are GU and AG. So the intron sequence is 5´-GUAAGC-intron-CAG-3´.

Excising the intron, the most likely sequence of the mRNA is 5´-G-exon1-AGUC-exon2-A-3´.

69 is the correct math for the amino acids