Question
According to the genetic code, the mRNA codons UGU and UGC code for the amino acid cysteine, the mRNA codon UGA is a stop codon, and the mRNA codon UGG codes for the amino acid tryptophan. What would a mutation in the second base of the codon UGA likely mean for the resulting protein? (SC.912.L.16.3)
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1 point
The resulting protein would most likely be unaffected.
The resulting protein would most likely be unusually long.
The resulting protein would most likely be unusually short.
The resulting protein would most likely differ by one amino acid.
*
1 point
The resulting protein would most likely be unaffected.
The resulting protein would most likely be unusually long.
The resulting protein would most likely be unusually short.
The resulting protein would most likely differ by one amino acid.
Answers
GPT-4o mini
A mutation in the second base of the codon UGA would change it to UAA or UGA, depending on the specific mutation. However, since UGA is a stop codon, changing the second base from G to A (resulting in UAA, which is also a stop codon) would not affect the resulting protein's length—in this case, it would remain a stop codon.
However, if the mutation changes UGA to UGG (the mutation is interpreted as replacing the first base with G on the second codon), UGG codes for tryptophan, which means the translation would continue and create a longer protein than expected.
Therefore, if we consider a mutation that results in the codon remaining a stop codon or changing to another codon that doesn't code for an amino acid, the most likely outcome if the translation continues is that the mutation would lead to a longer protein (if it changes to UGG) or to no effect (if it remains a stop codon).
Thus, the correct answer is: **The resulting protein would most likely be unusually long.**
However, if the mutation changes UGA to UGG (the mutation is interpreted as replacing the first base with G on the second codon), UGG codes for tryptophan, which means the translation would continue and create a longer protein than expected.
Therefore, if we consider a mutation that results in the codon remaining a stop codon or changing to another codon that doesn't code for an amino acid, the most likely outcome if the translation continues is that the mutation would lead to a longer protein (if it changes to UGG) or to no effect (if it remains a stop codon).
Thus, the correct answer is: **The resulting protein would most likely be unusually long.**