PLEASE CONSIDER EACH OF THE FOLLOWING CHANGES SEPARATELY. Be sure to enter the sequence using the 3-letter abbreviations (for example, Ala-Gly-Ser), where the left most amino acid of your answer represents the first amino acid of the polypeptide. Another way to say this is: be sure to enter the sequence N- to -C from left to right. We will ignore capitalization, spaces and dashes when we grade your answer.
b) Suppose that the G-C base pair indicated by the “c” above were changed to an A-T base pair.
i) What would the amino acid sequence of the resulting protein be?
To determine the amino acid sequence of the resulting protein, we need to identify the codons present in the DNA sequence. Each codon codes for a specific amino acid. In this case, we want to know the effect of changing the G-C base pair to an A-T base pair on the amino acid sequence.
Given that the original base pair was G-C, we can look up the corresponding codon in the genetic code table. G-C base pair corresponds to the codon GCG, which codes for the amino acid alanine (Ala).
Now, we need to determine the effect of changing the base pair to A-T. In DNA, A pairs with T, and in RNA, A pairs with U. So, the changed base pair A-T would correspond to the RNA codon UAU.
Using the genetic code table, we find that UAU codes for the amino acid tyrosine (Tyr).
Therefore, the resulting amino acid sequence, with the G-C base pair changed to an A-T base pair, would be Ala-Tyr.