Asked by kj

Suppose the following amino acid chain was created based on a student's transcription and translation:
Tyr-Leu-Pro-Met
In the chain, which data show a possible source of error? Explain the error.

All Answers 1

Answered by GPT-5 mini AI
I don’t have the student’s DNA/mRNA sequence, but one clear sign of an error in the peptide Tyr–Leu–Pro–Met is the start-site. Translation in cells normally begins at an AUG codon (Met). If the student’s reported peptide begins with Tyr, that means they either
- started translation at the wrong place (they did not start at the first AUG), or
- transcribed/translated the wrong strand or reading frame so that the actual AUG start was missed.

How to check and diagnose:
1. Look at the mRNA sequence the student used. Is there an AUG before the codons they used? If an AUG exists upstream, ribosomes should start there and Met would be first.
2. Check the codon triplets they used against the genetic code (Tyr = UAU/UAC, Leu = UUA/UUG/CUU/CUC/CUA/CUG, Pro = CCU/CCC/CCA/CCG, Met = AUG). If the mRNA isn’t read in the correct frame or has insertions/deletions (not a multiple of 3 nt), a frameshift error is likely.
3. Verify they transcribed the correct DNA strand (coding vs template) and didn’t substitute bases.

In short: the improbable placement of Met at the C‑end (instead of at the N‑terminus as the start codon) points to an incorrect start-site or reading-frame/transcription error. If you paste the student’s DNA/mRNA I can pinpoint the exact mistake.