Question

A scientist has sequenced a gene from a multicellular eukaryotic organism. Brendan claims that by analyzing the gene sequence and applying
the genetic code, he can conclude the sequence of amino acids in the protein that forms after the gene is transcribed and translated


Which statement provides the strongest evidence against the validity of Brendan's claim?


A. Regulatory proteins may activate or deactivate a gene, often by very complex mechanisms.




B. During transcription, a strand of mRNA is synthesized from complementary base pairs, with the substitution of uracil (U) for thymine

(T)




C. During translation, anticodons on tRNA bind to codons on mRNA as part of the process that forms the polypeptide.




D. After a gene is transcribed, introns are removed from the pre-mRNA to form the mRNA that is translated.

Answer 1

Answer:

D. After a gene is transcribed, introns are removed from the pre-mRNA to form the mRNA that is translated.

Explanation:

According to this question, a gene was sequenced by scientists from an eukaryotic organism. Brendan claims he can conclude the resulting protein after the transcription and trans of the gene.

It is true that transcription and translation are the processes that a gene undergo in order to be expressed i.e. produce protein. However, a gene sequence contains both the coding and non-coding regions in it. The coding regions code for a protein and are called EXONS in the mRNA while the non-coding regions do not encode proteins and are called INTRONS in the mRNA.

These introns are removed from the mRNA molecule that results from the transcription of a gene. The mRNA undergoes a process called SPLICING, which removes the non-coding part of the mRNA (introns) and joins the coding parts (exons).

Hence, if this occurs, Brendan will not be able to accurately conclude the resulting protein from that gene sequence because a portion of that gene will still be removed during SPLICING of post-transcriptional processing.