Using this mRNA codon chart, and the mRNA sequence you produced from the last question, provide the amino acid sequence for the protein that would be produced from this mRNA.
Use the shortened amino acid names given on the chart (ex. Arg, Phe, Met) and use a dash between each amino acid in your sequence (ex. Arg-Phe-Met). There should be only 24 amino acids in your sequence, even though you have 25 codons, because the last codon is a STOP codon, and does not code for an amino acid.
T he Correct Answer and Explanation is :
✅ Correct Answer (Amino Acid Sequence)
Assuming you have an mRNA sequence with 25 codons, and the 25th codon is a STOP codon, then you’re translating only the first 24 codons.
For example, if your mRNA sequence (not shown here) is:
5′-AUG-GCC-UUU-CAA-GGA-…-UGA-3′
(where UGA is the 25th codon — a STOP codon),
You would use the codon chart to find the corresponding amino acids for the first 24 codons.
Let’s suppose your codons translate to this amino acid sequence:
Met-Ala-Phe-Gln-Gly-Ser-Tyr-Leu-Asp-Val-Thr-Pro-His-Glu-Ile-Tyr-Asn-Cys-Trp-Arg-Leu-Glu-Asn-Gly
(This is 24 amino acids, and the 25th codon is a STOP codon, which is not translated.)
🧬 Explanation
Proteins are made through a process called translation, where a messenger RNA (mRNA) sequence is decoded to form a chain of amino acids. This sequence of amino acids folds into a specific shape to become a functional protein. The mRNA sequence is composed of codons, which are groups of three nucleotides. Each codon corresponds to a specific amino acid or a stop signal.
Translation begins at a start codon, usually AUG, which codes for the amino acid Methionine (Met). The ribosome then reads each subsequent codon on the mRNA, adding the corresponding amino acid to the growing peptide chain.
A codon chart (or genetic code table) is used to determine which codons correspond to which amino acids. For example, UUU codes for Phenylalanine (Phe), and GGA codes for Glycine (Gly).
There are 64 possible codons but only 20 amino acids. This redundancy means multiple codons can code for the same amino acid. However, three codons (UAA, UAG, and UGA) are known as STOP codons — they do not code for any amino acid. Instead, they signal the end of translation.
In this case, although the mRNA has 25 codons, the 25th is a STOP codon. That means the ribosome stops translation when it reaches the 25th codon. As a result, only the first 24 codons contribute to the amino acid sequence. Therefore, the final protein is made up of 24 amino acids.
Understanding how mRNA translates into proteins is fundamental to molecular biology and biotechnology, including genetic engineering, medicine, and understanding hereditary diseases.
