Question at position 18 A sequence of eukaryotic mRNA that reads: 5'-GpppCCUGUGGACAUGCCUGAAUCAGCUUUAAUCUGAAAAAAA-3' should code for ____ amino acids after all steps of conversion into protein are complete.7101168Clear my selection

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BlackTom AI · Accepted Answer

Question restatement: The given sequence is an eukaryotic mRNA that reads 5'-GpppCCUGUGGACAUGCCUGAAUCAGCUUUAAUCUGAAAAAAA-3'. It asks how many amino acids are coded after all steps of conversion into protein are complete, and provides options: 7, 10, 11, 6, 8.

Option A: 7. To evaluate this, we look for the open reading frame (ORF) starting at the first AUG in the coding sequence, since in eukaryotes translation typically begins at AUG. The segment contains an AUG at CAUGCCU... so the start codon is AUG. Translating from this AUG in the standard reading frame:
 - AUG = Met
 - CCU = Pro
 - GGA = Gly
 - CAU = His
 - GCC = Ala
 - UGA = Stop
This yields a peptide of five amino acids (Met-Pro-Gly-His-Ala) before a stop codon halts translation. If one mistakenly includes the stop or miscounts, some learners might arrive at a number like 6 or 7, but the canonical count of amino acids encoded by the ORF before hitting the stop codon is 5. Therefore, 7 would require counting a portion of sequence outside the canonical ORF or assuming an alternative counting method.

Option B: 10. A reading frame that somehow yields 10 amino acids before a stop would require a much longer uninterrupted ORF. In the standard frame starting at the first AUG, the first in-frame stop appears after five codons, giving 5 amino acids total. There is no immediate evidence of a longer ORF in this frame without introducing additional stop-free codons or shifting frames. Thus, 10 is not consistent with the straightforward interpretation of the ORF here.

Option C: 11. Similar to option B, claiming 11 amino acids would imply a longer ORF or a different frame without an early stop. The sequence provided, when read in the typical frame starting at AUG, encounters a stop codon (UGA) after five codons, so 11 is not supported by the standard translation logic for this sequence.

Option D: 6. This is close to the five-amino-acid count, but it would require either counting the initiating Met and a single extra codon before a stop in a nonstandard frame or incorrectly including the stop codon as an amino acid. In correct interpretation, the stop codon does not count as an amino acid, so 6 would be inaccurate for the canonical ORF from the first AUG.

Option E: 8. Similar reasoning to option D: to reach 8 would necessitate a longer ORF than the first AUG frame provides, or miscounting the stop codon as an amino acid. The canonical reading frame yields 5 amino acids before a stop, so 8 is not correct under standard rules.

Summary of reasoning and common pitfalls:
- Key concept: In eukaryotes, translation usually starts at the first AUG. Translate codons until you hit the first stop codon (UGA, UAA, or UAG). The stop is not counted as an amino acid.
- In this sequence, the first AUG is followed by five codons before a UGA stop, giving Met-Pro-Gly-His-Ala = 5 amino acids.
- Some students miscount by including the stop codon as an amino acid, or by starting translation at a different AUG in a shifted frame, which may yield different numbers such as 6, 7, or more. However, those approaches do not reflect the standard interpretation of the ORF for this specific sequence.
- The option set provided does not include the canonical count of 5, which suggests either a mismatch between the canonical interpretation and the given keys or an intent to test awareness of reading frame and stop codon rules rather than simply counting codons.

Note: If we strictly adhere to standard molecular biology rules (start at first AUG, stop at first in-frame stop codon, do not count the stop), the correct count would be 5 amino acids for this sequence. Any option that claims 7, 10, 11, 6, or 8 would require deviations from that strict interpretation (such as counting differently or selecting an alternative frame), which are common sources of error in these problems.

Question at position 18 A sequence of eukaryotic mRNA that reads: 5'-GpppCCUGUGGACAUGCCUGAAUCAGCUUUAAUCUGAAAAAAA-3' should code for ____ amino acids after all steps of conversion into protein are complete.7101168Clear my selection

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Question at position 22 What does a ribosome read during translation?mRNAtemplate strand of DNAcoding strand of DNA

Question at position 25 A sequence of eukaryotic mRNA that reads: 5'-GpppCCUGUGGACAUGCCUGAAUCAGCUUUAAUCUGAAAAAAA-3' should code for ____ amino acids after all steps of conversion into protein are complete.6781110Clear my selection

_______ is the process in which a protein is assembled at a ribosome.

The bottom loop of the tRNA molecule is called the . This sequence recognizes and pairs with the on the mRNA.

What process converts the mRNA "message" into a sequence of amino acids?

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Question at position 18 A sequence of eukaryotic mRNA that reads: 5'-GpppCCUGUGGACAUGCCUGAAUCAGCUUUAAUCUGAAAAAAA-3' should code for ____ amino acids after all steps of conversion into protein are complete.7101168Clear my selection

查看解析

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类似问题

Question at position 22 What does a ribosome read during translation?mRNAtemplate strand of DNAcoding strand of DNA

Question at position 25 A sequence of eukaryotic mRNA that reads: 5'-GpppCCUGUGGACAUGCCUGAAUCAGCUUUAAUCUGAAAAAAA-3' should code for ____ amino acids after all steps of conversion into protein are complete.6781110Clear my selection

_______ is the process in which a protein is assembled at a ribosome.

The bottom loop of the tRNA molecule is called the ______. This sequence recognizes and pairs with the ______ on the mRNA.

What process converts the mRNA "message" into a sequence of amino acids?

更多留学生实用工具

希望你的学习变得更简单

The bottom loop of the tRNA molecule is called the . This sequence recognizes and pairs with the on the mRNA.